Examples of Non Invasive BISF Survey Reports.

All potential home buyers at one point or another, will need to instruct a surveyor to carry out a survey or home buyer report. Your mortgage company needs to know that the property you wish to buy is in good condition with no major defects and worth the value that you intend to pay for it. Here we will take a look at two examples of Non Invasive BISF house surveys, the fist being a homebuyers survey and the second being a less common, specific defects survey.

They can be quite long and repetitive but worth reading.

BISF houses undergo the exact same survey as any other property.

With any Non-Traditional construction, it is critically important that your surveyor is familiar with your particular construction type and truly understands the building method involved, in order to compile an correct and reliable survey report.

IMPORTANT:  Before you instruct or finance a survey!

Does the house have a corrugated asbestos roof?

If the property has a corrugated asbestos roof then please check that your chosen mortgage company does in fact lend on BISF properties that still have the original corrugated asbestos roof fitted. It’s important to do this, before you pay for a survey. This is because an increasing number of lenders are turning down mortgage applications on system built properties (including BISF houses), with asbestos based roofing materials. The lenders published Lending Criteria should contain these details.

Do your homework first as surveys are expensive and non refundable.

Examples of a non intrusive BISF survey report & Home buyers report.

Non Intrusive simply means that whilst conducting the survey, no effort is made to access non exposed sections of the property or any covered or enclosed section of the steel frame or any other non-visible support structure of the property. In this case, the surveyor will base the report on visually exposed areas of the structure only.

In a BISF property, the loft space and visible steel roof support, contains the only exposed, non covered parts of the buildings support structure.

Invasive Surveys

An invasive survey, if requested, will involve either the removal of a small section or sections of internal or external walls, so that portions of the steel stanchions can be visibly inspected. Surveyors are usually hesitant to do this due to the cost involved in repairing and sometimes re-plastering or re-rendering of the removed internal wall board or external surface.


A much simpler method to gain visible access to the base structure is by using a borescope. A video borescope or “inspection camera” uses a miniature video camera at the end of a flexible or rigid fibre optic tube. The tube is passed through a small hole into the wall cavity allowing the structure to be viewed internally without requiring major repair work. However the borescope is not suitable for all situations.

Before we look at the surveys it is helpful to know what the surveyor will and will not do during the survey of your house.

Outside, the surveyor will make a visual, non-invasive inspection of the main building and all permanent outbuildings and boundary walls and areas in common or shared use by walking the area.

Landscaping and temporary outbuildings are not inspected.

The surveyor will inspect high level surfaces and features from ground level within the boundaries of the property or from neighbouring public property or by using a ladder where it is safe to do so and at a height of no more than three metres above a flat surface. The surveyor will not climb or walk on roofs of any sort.

Inside, the surveyor undertakes a visual, non-invasive inspection. The surveyor does not force or open up the fabric of the building, including any fixed panels or electrical fittings, does not take up carpets, floor coverings or floorboards, move any heavy furniture or remove contents of cupboards.

The surveyor will inspect the roof structure from inside the roof space where safe access is available, and will move around the roof space where this does not present a risk to either the surveyor or the property, but will not lift any insulation material or move stored goods or other contents.The surveyor may check for damp using a moisture meter and check floor surfaces and under floor voids if accessible but will not move furniture or floor coverings to do so. The surveyor will not comment on sound insulation or noise of any sort.

Where there is any risk of damaging the fabric of the property, the surveyor will limit the inspection accordingly but will note this in the report.

The surveyor inspects those parts of the gas, electricity, water and drainage services that can be seen but will not carry out specialist tests on the services or assess the efficiency. Other services that may be present ( such as security systems, telephone or broadband services etc) are not inspected or reported on.

Home Buyers Survey Example


156 Bisf Drive


Please note that this Report is solely for your use and your professional advisers’ and no liability to anyone else is accepted. Should you not act upon specific, reasonable advice contained in this Report, no responsibility is accepted for the consequences.

The Report has been prepared in line with the Description of the Homebuyer Service already provided. If any addition to the standard Service was agreed before the Inspection, this is confirmed at the foot of the last page.

The principal aim of the Report and Valuation is to help you to:

  • Make a reasoned and informed judgement on whether to go ahead with the purchase.
  • Assess whether or not the property is a reasonable purchase at the agreed price
  • Be clear what decisions and actions should be taken before contracts are exchanged

The general condition and particular features of the Property are covered, but the Report focuses on the matters, which the Surveyor judges to be urgent or significant.

‘Urgent matters’ are defects judged to be an actual or developing threat either to the fabric of the building or to personal safety; it will be advisable to have these put right as soon as possible after purchase (in some cases even before). ‘Significant matters’ are those which, typically, in negotiations over price would be reflected in the amount finally agreed.

Matters assessed as ‘not urgent’ or ‘not significant’ are those outside the scope of the HOMEBUYER Service and are generally not reported. However, other matters (such as legal and safety considerations) are reported where the Surveyor judges this to be helpful and constructive.

If – after reading and considering all the information and advice in the Report – you decide to proceed with the purchase, then there are probably some things on which you should take action at once. Each such item is highlighted in the report with the word ACTION and is also listed in Section F, together with advice on what to do next.


Below are the Surveyor’s conclusions, in brief, on whether or not this Property is a reasonable purchase at the agreed price, and on particular features which affect its present value and may affect its future resale. The opinion takes no account of factors outside the scope of the HOMEBUYER Service.

It is hoped that this overall view will help you to keep in perspective the detailed facts and advice which follow. You are asked to bear in mind particularly that it can be misleading to treat individual matters in isolation. So that you may use this Report to best advantage in reaching your decision on whether or not to proceed with the purchase of this Property, you are most strongly advised to read and consider its contents as a whole.

This semi-detached BISF constructed dwelling is generally in good condition for its age and design. There are no essential repairs for mortgage purpose and the purchase price is not considered excessive in the current market.


This section covers the important general background information on the Property and its location, including amenities and features of vicinity as well as any environmental and other wider considerations. It also includes the state of occupation and the weather at the time of the Inspection.

Type and age
The property is a purpose-built two-storey BISF house built around 1945.


The building is a Non-Traditional construction steel framed house.
The external walls of the ground floor are of a cement render applied to metal laths, whilst the walls of the first floor are constructed using vertical steel sheeting, fixed to rails and bolted to vertical channels, which extend to join the laths. This upper sheeting has further been over clad using white UPVC profile sheeting. Floors are solid and are of concrete construction.

Ground floor: Entrance hall, reception room, Dining room, kitchen

First floor: 3 bedrooms, landing, bathroom

Garage and grounds
There is no garage. There is a wooden framed outbuilding attached to the side elevation of the property.

This post war house is situated in a reasonably quiet cul-de-sac close to a public park and within a mile of comprehensive shopping and traveling facilities at Mere Green including the Four Oaks Railway station. The immediate area is mixed with some local authority housing and prestigious private residencies.

It was dry at the time of the inspection.

Limits to inspection
The roof covering and gutters could not be inspected. At the time of the inspection the property was occupied and furnished with fixed floor coverings.


Movement, steel & timber defects and dampness are, in their various forms, the three greatest potential threats to the structure of a building. Where evidence is found of any of these conditions, advice is given on what action should be taken. (Where a problem is judged to be serious, it might prove necessary for a separate, detailed examination to be undertaken – perhaps by specialists. For example, the foundations might have to be laid open to analyse the cause of some structural movement, or the full extent of timber rot might require further investigation.)

There were no signs of significant cracking, current settlement, subsidence or structural movement in this property.

Timber defects
During our visual inspection there was no obvious evidence of significant timber decay in this property.

Steel Defects

During our visual inspection there was no obvious evidence of significant steel corrosion in this property.

Dampness and condensation
We cannot confirm whether a damp-proof course is present or not on the external elevation. However it is likely a property of this age and type would have been built without the requirement due to the non-traditional nature of construction and having no brick or block walls at ground level. Where access could be obtained, moisture readings were taken internally at regular intervals and we found no sign of significant rising or penetrating damp in this property. There is no evidence of significant condensation in this property.


The general standard of thermal insulation is generally low. The loft cavity is well insulated by a triple layer of Rockwool insulation material.

The level of insulation appertaining to exterior walls cannot be ascertained without an invasive search.

The roofs, chimneys and other external surfaces of the building are examined from ground level, where necessary from adjoining public property and with the help of binoculars. The roof structure is examined from inside the roof space where accessible (insulation material, stored goods and other contents are not moved or lifted). The efficiency of rainwater fittings (gutters and downpipes) can only be assessed properly during the Inspection if there is heavy rain.

Roof structure and covering
The roof is shallow pitched with mock tile profile metal roofing sheets incorporating a protective coating. The water from the roof drains into a upvc guttering system. It was difficult to obtain a full view of the roof coverings from ground floor levels. A view was possible from balconies to the upper levels. The mock tile coverings are in good condition although a type of green algae coats the surface. There is no evidence of any corrosion to the profile. The gutters appear to be satisfactory. You should be aware that these are vulnerable to blockages and leakage although due to height restrictions no visible check has been undertaken. The metal flashings appear to be in satisfactory condition where visible externally. Overall the roof appears to be in a good serviceable state of repair.

Flue visible to the rear pitch of the roof. The homeowner informs us that the lower section of the flue into the house has been removed and the living room is heated by way of a flue-less gas fire that requires no flue.

Rainwater fittings
Rainwater goods are in satisfactory condition.

Main walls

Horizontal plastic cladding at high level with pea shingle render at low level.
The non cavity walls appear true and plumb with no evidence of significant structural movement. The lower rendered finish is generally satisfactory and there is no evidence of any serious cracking or ongoing structural movement. However it was noted that the upper elevations are covered in UPVC cladding. A partial view of this cladding was possible from the windows to the front & rear elevations. This appears satisfactory although the type or condition of the fixings used to affix the cladding onto the original steel panels could not be viewed. There was however no signs of warping or splitting to the cladding and nothing visible to suggest otherwise.

External joinery
The property is fitted with Crittal Hope steel window frames incorporating white UPVC double glazed windows and UPVC doors. The double glazed units appear generally in good condition.

External decoration
The external decorations were found to be in good condition. The original galvanised Crittal Hope windows frames showed no signs of corrosion but would require re-painting in the near future.


Floor surfaces and under-floor spaces are examined so far as they are accessible (furniture, floor coverings and other contents are not moved or lifted). If a part or area normally examined was found to be not accessible, this is reported; if a problem is suspected, advice is given on what action should be taken. It is not possible to assess the internal condition of any chimney, boiler or other flues. (In some cases, when furniture and pictures are removed internal decorations may prove to be damaged or faded.)


Roof space
The loft space to this property is accessed via a hatch in bedroom one. The roof is non-traditional steel trussed rather than rafter design and the steel supports were found to be satisfactory taking into consideration the age of the property as were the visible fixing bolts. No significant corrosion was visible other than very slight surface corrosion on unpainted areas of the structure. The profile metal sheeting rests on wooden batons, which are secured onto angled steel purlins. The timber appears to be in satisfactory condition. The roof space has been insulated and party walls are properly in place.

Generally those sections of roof void that were visible are in satisfactory condition.

The ceilings that are formed of plasterboard are in good condition and have been painted.

The solid floors are with no evidence of subsidence or settlement. However it was difficult to obtain a full view of the floors because of fitted laminate flooring throughout the property.

Internal walls and partitions
The internal walls and partitions consist mainly of plastered timber studwork and lightweight proprietary hollow-cored partitioning finishes. The owner informs us that the original hardboard wallboards have been removed and replaced with new plasterboard and internal insulation throughout the property around 3 years prior to the survey. Some slight cracking was noted to the plaster work to bedroom one and internal partitions have settled very slightly. However this is not considered to be of structural significance.

Fireplaces etc.
There are no open fireplaces. Subsequently there are no chimney breasts to this property other than those removed by the occupier and mentioned previously.

Internal joinery
The internal joinery is in good condition and is of an acceptable standard. The internal doors appear solid serviceable and well maintained. The kitchen fittings appear modern. Skirting boards are non original and are satisfactory.

Internal decoration
The internal decorations of this property appear to have been carried out to a high standard. No visible faults requiring remedial work was visible.


The efficiency, compliance with regulations and adequacy of design of services can only be assessed by tests conducted by suitably qualified specialists. Although surveyors are not specialists in these particular areas, an informed opinion can be given on the basis of the accessible evidence. Where possible, drainage inspection-chambers are examined (except in the case of flats), but drains are not tested during the Inspection. However, in all cases advice is given if there is cause to suspect a problem. Leisure facilities and non-permanent outbuildings are noted but not examined.


The electricity meter is located under the stair void to the ground floor entrance hall and accessed by an exterior door. The consumer unit is located directly above the meter and appears to be satisfactory. Generally the installation appears satisfactory. Ideally electrical systems should be inspected every year.

The property is served by Gas is connected to the property. The gas meter is located at the end of the entrance hall and is enclosed by a fitted cupboard. The unit appears satisfactory.

The property is connected to the water mains. An outside stopcock is located on the pavement to the front of the boundary. The internal stopcock is located under the kitchen sink. Visible plumbing is formed in copper and PVC and found to be generally satisfactory. The property is heated via a wall mounted combination boiler located on an outward facing interior wall of the kitchen. This unit also provides hot water for the property. Service records show that the boiler appears to have been maintained on a regular basis. The property requires no loft water storage tank. The sanitary fittings are modern and in satisfactory condition.

The property is fitted with a central heating system. Radiators are located in each room of the house. The radiators are served by the afore-mentioned boiler unit. At the time of inspection the central heating was operative and all radiators appeared hot to the touch and assumed to be functioning.

There are no other common services and there is no passenger lift.

Rainwater drainage
Soil and foul water drains via pipework which is concealed within the property and drains via an exterior plastic stench pipe located at the rear elevation.. Aside from this no further comments can be made because extensive opening up works would have to be undertaken to expose the system. It was noted that there was a manhole cover to the front of the property though it was not difficult to lift the cover. Without extensive exposure work we cannot confirm the type or layout of the underground rainwater drainage system.

The site
There is no separate covered car parking space.


Your Legal Advisers are responsible for checking relevant documents relating to the Property (these might include servicing records and any guarantees, reports and specifications on previous repair works) as well as for carrying out all the standard searches and inquiries. However, if any specific matters are identified which the Legal Advisers should investigate on your behalf, these are reported in this section. You are asked to pay particular attention to the ACTION paragraph at E4 below.

We understand that the property is freehold with no known restrictions.

Regulations, guarantees and other matters
Your solicitor should confirm the property is Freehold.


Assuming that you decide to proceed with the purchase of this Property, there may be some things on which you should take action before you exchange contracts – such as obtaining competitive quotations for urgent repairs. (If any further investigation of some urgent matter is recommended, this will involve a second visit to the Property, perhaps by an appropriate specialist who will submit a separate report.)

No copy of this report need go to your legal advisers. No urgent repairs are necessary on this property. We recommend that you consider a full structural survey report in order to confirm that the non-visible support structure and steel stanchions are in good order. In rare cases they have been known to suffer from corrosion due to water ingress resulting from poor exterior maintenance or condensation caused by inadequate ventilation.

Maintenance considerations
Other than the normal maintenance work, which is required for a property of this type and age, there are no other significant items to bring to your attention.

Other considerations

British Iron & Steel Federation Properties are associated with a list of potential defects.

Whilst not all the defects listed are serious, you should be aware of the association to this type of property.

Potential Defects

  1. Corrosion Of:-
    1. Expanded Metal Lathing
    2. First Floor Steel Wall Sheeting & Fixings
    3. Cowling
    4. Structural Frame
    5. Stanchions, in particular base of stanchions.
    6. Roof Trusses
    7. Holding Down Bolts & Packing
    8. Sheeting tail
    9. Cast Iron Flues
  • Cracking of external render
  • Deterioration of asbestos cement roof covering
  • Cracking of concrete plinth (mainly due to 7 above)
  • Sulphate contaminated fill below floor slab.

Exterior surface maintenance to the property throughout its lifespan has been known to significantly reduce the likelihood of potential defects.

This Non Traditional dwelling is situated in a prestigious residential area close comprehensive shopping and traveling facilities at Mere Green & Sutton Coldfield. This area has seen significant price rises in the last year. Externally the property is in good condition for its age and design and in many ways has suffered less than a traditional property of a similar age. Internally the house is well presented although and having the benefit of central heating. There is likely to be a high demand for this type of property on resale and given its location and the fine views of nearby countryside, the purchase price is considered reasonable and your purchase is recommended.


In arriving at the opinion of the Property‘s Open Market Value as defined in Section D* of the Description of the Homebuyer Service, a set of standard assumptions is adopted, subject to any change stated below. Legal Advisers, and others who undertake property conveyancing, should be familiar with the assumptions and are responsible for checking those concerning legal matters. The opinion of the Open Market Value given below could be affected by the outcome of the inquiries by your legal Advisers [Section E] and / or any further investigation and quotations for urgent repairs [section F]. The valuation assumes that your Legal Advisers will obtain satisfactory replies to their inquiries relating to the assumptions made in this Report.

In our opinion the Open Market Value on 18th December 2011 of the Freehold interest in this property as inspected, with vacant possession was £166,000 (one hundred and sixty six thousand pounds).

The current cost of reinstating the property in its present form is estimated for insurance purposes to be approximately £82,000.

This report is provided in accordance with the terms of the Description of the Homebuyer Service previously supplied, subject to any agreed addition noted below.

The report is solely for your use and your professional advisers’, and no liability to anyone else is accepted. Should you not act upon specific, reasonable advice contained in the Report, no responsibility is accepted for the consequences.

I hereby certify that the Property has been inspected by me and that I have prepared this Report, including the opinion of Open Market Value.


SURVEYOR’S NAME: Mr. xxxxxxxx


sold sign

2. Specific Defects Report of a BISF Property.

This specific defects report was compiled at the request of the homeowner and is a less common report.

To keep the report concise we have removed some text regarding the identity of the surveyor and the property.

Our client has had a Mortgage Report which has identified the property as being steel framed, we have not seen this report. We would be happy to comment further if a copy of this is forwarded to us.
Mr XXXX has instructed us to carry out a visual inspection on the property and comment on our findings with regard to the steel frame.
We would advise that we have not opened up the structure to inspect it as this goes beyond the scope of the report and we didn’t have the appropriate permissions or skilled labour on site to open up and re-inspect the property.We would be more than happy to inspect the frame if you obtain permission & and make suitable arrangements with the existing owners to open up the structure and to make good the structure and redecorate as necessary.

Chimney: Flue visible to the rear pitch of the roof
Main Roof: Profile metal roofing with a protective coating, shallow pitch
Gutters and Downpipes /Soil and Vent Pipe: Plastic
Walls: Horizontal plastic cladding at high level with ;pea shingle render at low level
Structure: Metal structural frame
External Joinery: Double glazed plastic
Foundations: Not inspected (assumed a stepped brick ;foundation)

Ceilings: Originally hardboard, replaced with plasterboard, not opened up or exposed.
Walls Assumed originally hardboard finished, not opened up or exposed. The walls were examined as being dry lined with plasterboard (assumed from tapping). We were additionally advised by the owners/occupiers that they have double plaster boarded the party wall and skim coated the remainder of the property with plaster.


Ground Floor:Solid underfoot, assumed concrete

First Floor:Assumed joist and floorboards within the metal frame

We have used the term ‘assumed’ as we have not opened up the structure.

Structural Frame

From our visual inspection detailed within this report we have been able to see the structural frame within the roof and in this area we have examined the fixing bolts and the condition of the structural steel frame and associated steel frame and are satisfied that it is in appropriate condition for its age, type and style.

The high risk areas with this type of building in our experience are at ground level. We can see no factors such as sloping grounds or excessive condensation within the property that we feel would promote deterioration of the structural frame or/and the fixing at low level. We would advise we have seen approximately ten percent of the entire structural frame and this is within the roof void.

Other issues with non traditional buildings
This is known as a BISF building as it was developed by the British Iron and Steel Federation. Your solicitor needs to specifically ask the present owners:
1) If the original asbestos roof and associated elements in asbestos have been completely removed as in our experience asbestos in a property whether it is in a poor and dangerous condition or not puts prospective purchasers off.

2) The property has been overclad with a plastic cladding and a render. Full details need to be obtained of this, for example was the original metal cladding removed (in the roof area we can still see the metal cladding) and is there insulation between the original structure and the new plastic cladding. Condensation can be an issue.

3) Corrosion can occur to the steel frame particularly at the base and around the windows and doors. Was any corrosion noted when works were carried out? Is there a record of such corrosion in adjoining properties? These questions need to be specifically directed at the Local Authority. As mentioned we are happy to return with the structure opened up and suitable permissions.
You need to obtain further specialist advice on these points.

Time Line – A brief history of the structure

From discussions with the present owners and nearby property owners and occupiers we have developed the following Time Line.

Circa 1945 Built original construction shallow asbestos roof profile, metal cladding to the walls, single glazed windows.
1980 Plastic cladding and render added, double glazed
2000 Double layer of plasterboard added to party-wall and skim plastered over the internal hardboard lining (assumed)


Our inspection has been specifically related to the steel frame structure issues detailed below.:

(At this point photographic images may be used showing the various aspects of the property listed below)

Visual Inspection
Our inspection has taken the format of a visual inspection:
1. External of the property of the:
i. Front elevation
ii. Rear elevation
iii. Right hand side elevation
No opening up has been carried out.

2. Internal of the property
No opening up has been carried out.
We have viewed:
Ground Floor
i. Hallway
ii. Front reception room
iii. Rear dining room
iv. Rear kitchen
v. Side room

First Floor
vi. Front bedroom
vii. Rear bedroom
viii. Bathroom

3. We inspected the Roof space where we could see the steel frame and the profile metal cladding.

(photographs may be shown of the internal roof structure and close up images of the steel frame)


1. From our visual external inspection we noted:
i. The roofs are profile metal sheets externally with insulation visible internally. To be confirmed whether asbestos is still present.
ii. The walls are plastic cladding at high level and pea shingle render at low level
iii. Windows are replacement double glazed plastic windows
We were unable to see the steel frame.

2. From our visual internal inspection we noted:
i. Ceilings plastered and painted/papered
ii. Walls – plastered and painted/papered
iii. Floors Ground floor solid underfoot, assumed concrete.
First Floor joists within the metal frame.

3. From our visual inspection within the roof we were able to see:
i) The structural frame and profile metal sheets which were in average
condition for it’s age, type and style.

i) We were unable to see the structural frame with the exception of
within the roof.
ii) We have not moved furniture or fixtures and fittings.
iii) The full areas inspected are identified within the inspection part of
this report and the terms and conditions.

(The report may also include some history relating to Non-Traditional Housing Construction for the benefit of both the customer and Mortgage underwriters.)


Non traditional housing defined
This refers to construction which has a manufacturer process basis. It is typically a metal or concrete or timber frame building although sometimes it is formed from large concrete panel construction. It is considered a move away from traditional construction which was a brick or stone or timber but ironically this type of construction has changed as well over the years.
The main types of non traditional construction:
First World War
In the period of 1919-1939 when 4.5 million houses were built it is said that less than 250,000 of these were non traditional of which the majority were built for the Local authorities. Scotland had a predominance of these houses during this period. The houses took the form of insitu concrete, timber, steel and sometimes cast iron. A classic style of property would be the Telford steel framed house from the 1920’s which was steel framed and steel-clad.

Second World War
After the Second World War the need for housing, the lack of skilled labour and factories that had been set up for the War effort that could be amended to house construction led to a boom in non traditional housing. The houses took the form of steel and aluminium framed system (surplus from the war effort), precast and insitu concrete and timber frame. Typical houses were Cornish unit which was a pre-cast reinforced concrete house, Swedish timber which was a pre-fabricated timber house and a BISF house which is a British Iron and Steel Federation house which is steel framed and clad.

The BURT Committee was an influence in this age looking for efficiency, economy and speed of construction in building.
1940’s, 1950’s and 1960’s
Slum clearance and redevelopment of town centres. Move towards industrialised buildings in factory controlled conditions were meant to give a better product with assembly being carried on at the site itself. Large panel system building led to high-rise construction. Closed systems are when the product is as manufactured, Open Systems allow for a degree of alteration.
Rationalised Traditional Construction known as RAT-TRADS is a cross wall construction from the 1960’s onwards. This popular form of cross wall construction was used and the front and rear elevations were filled in with panels.
Up to the late 1970’s, early 1980’s all types of construction were being used, steel, timber and concrete framed systems, LPS which is large panel systems.

Volumetric and RAT-TRAD. World in Action TV programme, early 1980’s is said to have stopped the non-traditional building industry in it’s tracks particularly the timber frame industry (although it is said that it didn’t affect Scotland that much).
BRE reports later on found no evidence of the decay that World in Action considered to be widespread.

The Ronan Point collapse
A twenty-two storey large panel concrete construction which had an explosion on the 18th floor causing the collapse. This was due to the lack of restraining ties which was as designed (not due to bad workmanship).

1960’s and 1970’s Volumetric Box Construction – Prefabricated and lifted into place.

Non Traditional Constructions Overview

There are considered to be around 1 million properties built from non-traditional construction. BRE have over 500 systems listed between 1900 and 1976 excluding RAT Trad post 1976 timber-framed construction. The main forms of non-traditional construction are as follows:

Problems associated with types of non traditional buildings

In non traditional houses there are a selection of problems:
Metal corrosion of the metal frame particularly around the lower sections of the stanchions and the windows and doors.
Thermal efficiency problems
The irony of non traditional and traditional construction
Interestingly the construction often classified and termed as traditional construction has changed and altered considerably since the War Years when solid walls in brick or stone have now become cavity walls. The inner wall has become block which has changed in material and thickness many times as has the wall ties that hold the two walls together. Non traditional houses can suffer from a lack of understanding of the system and an unfamiliarity particularly with surveyors who don’t specialise in this area. There can also be problems with mortgage companies lending and holding market value.

BISF House Information Sheet
A pre-fabricated steel structure originally built with a shallow pitched asbestos roof, panelling to higher level and render to lower level. Between the metal frames are timber struts and insulation with an inner plasterboard or hardboard.
Selective Problems
This is due to corrosion and deterioration of the frame that is hidden by the structure. Also the properties are poorly thermally insulated for today’s standards and also there is noise transfer between buildings. Improvements to bring up to current standards could involve a thorough check of the steel frame, replacement of the asbestos roof and increase in insulation without promoting condensation and a reduction in the noise transfer between the properties with the addition of new double glazed windows. We have had costs quoted at between £20,000 – £50,000 depending upon the alterations already taken place and mortgage company requirements.

Improvement costs in 2004
Structural render £8k
Roof insulation £4.3k
Windows £2.1k
PVC doors £1k
Fascias and soffits and rainwater goods £0.5k
Bathrooms £0.9k
Central heating £2.3k
As the vast majority of houses sold in the UK are mortgaged it is essential that these properties are mortgageable to sell to the majority of the market.

Specific Problems Asbestos roof
When deteriorating asbestos can be a health hazard, complete replacement is recommended. The roof material has to be appropriate for the strength of the roof structure and in our experience they need replacing with a profile metal sheet and insulated. However this also needs to be ventilated to prevent corrosion from occurring.

Steel Structure
Risk of deterioration to the base of the steel structure and around the window areas and high humidity areas such as bathrooms and kitchens.

Profile metal sheeting to the upper areas and a render on an expanded metal lath to the ground floor areas with a timber frame and a fibreglass insulation and plasterboard. The frame is formed with rolled steel angles and channels. The roof is formed from tubular steel trusses which we believe are mock truss centrally (this needs to be checked and confirmed).

Improvements in the insulation can result in condensation. External structural insulation panelling is recommended which is difficult to do (unless both yourself and the neighbouring property are carried out otherwise there will be a step in the external wall).
Structherm is often quoted as the only suitable insulation rendered panel system as this is accepted by ninety per cent of the mortgage companies (obviously subject to variations in the market) and is available with a long-term guarantee.

Windows and Doors
Originally steel frame timber glazed. Now the majority have been replaced with double glazed windows.
Party Wall
The dividing wall between properties. We have seen quoted as 30mm thick or as a studwork.
Surveyors inspections can take the form of a non intrusive visual inspection or in the form of an intrusive/destructive inspection where the walls are opened up exposing the framework. Some reports say the use of borescopes however in our experience borescopes do not give a suitable view of the area so we would recommend opening up of the structure.
BISF Information and Action Required
You need to establish the exact mortgage requirements on the property at the time that you wish to purchase as these will change from time to time.


    1. They may vary from house to house. This was originally my concern, but I never hear the neighbours even though they have several young children.

      Looking in the loft, the party wall is breeze block. At just above ceiling level the wall appears to change from a double thickness of blocks to a single thickness.

      In the rooms the breeze block walls are dry lined with board on timber studwork, so going from one house to the other you will have board>air gap/timber studwork>double layer of breeze blocks>air gap/timber studwork>board, which I think provides better than average noise insulation. Traditionally built houses would just have the concrete blocks or bricks and no additional air cavities to dampen the noise.

      You might find that the party wall construction varies from location to location. For example, here in Bath the outhouses are built of breeze block, but other people report theirs are only built of wood.