Atholl Steel Framed House 1945 Variant
- Manufacturer: Atholl Steel Houses Ltd
- Variant: 1945 Version
- Construction Type: Steel Framed
- Consultant: Sam Bunton, LRIBA
- Period Built: 1945-48
- Number Built: 1600
- AKA: Atholl Post-War
- Example Build Location: Garscube 1946
History Atholl Steel Houses
Atholl Steel Houses was formed by Sir William Beardmore and the Duke of Atholl in 1924. The company built prefabricated houses from standard steel parts produced at the Beardmore steel plant at Mossend.
Pre-1944: The Atholl Steel House Company had already built a large number of houses in Scotland, during the years immediately after the first World War. In the period between 1926 and 1928, 550 Atholl houses were built in Scotland. These houses, using a steel framework clad externally with steel sheeting, were erected by Local Authorities and the Second Scottish National Housing Company. During the same
period, in England, 252 Atholl steel houses were erected on Watling Estate, Burnt Oak for London County Council. About 50 further dwellings were distributed between several other Local Authorities.
1944: In October 1944, Atholl Houses Limited, successfully put forward proposals to increase their output to the Interdepartmental Committee on Housing Construction, otherwise known as the Burt Committee, who initially placed a pilot order for 100 Atholl Houses early in the year, before subsequently approving a further order for 1500 houses which were built in 1947-1948.
Research indicates that it is very likely that all the proposed 1945 Atholl houses, were erected as four in one blocks. A pair of semi-detached houses would be split into 4 individual, flat style apartments, with front and side access to ground and first floor levels respectively.
By early 1948, the supply of steel declined drastically. The Cabinet Office’s Central Economic Planning Staff were forced to restrict the use of steel, to just one ton per house. The production of steel and steel-framed houses would also cease, and manufacturers of steel rich, non-traditional houses were ordered to drastically reduced the steel content of their properties.
All new proposals would require Cabinet Planning Committee consent. Atholl responded to these restrictions by designing a modified version of their design, which retained the inner steel frame but instead used 100 mm bricks and an inner leaf of timber studding, finished with plasterboard in place of the original steel sheeting.
The construction methods used in the Atholl 1945 steel houses are essentially very similar to the earlier 1926 version, the details of which can be viewed HERE.
The 1945 version received several upgrades including, but not limited to; improvements in architectural design, sound insulation and more efficient thermal insulation. This particular design was also Burt Committee approved.
The main identifying features which differentiate between the 1920s and 1940s dwellings
are as follows:
Main differentiation between 1920s & 1940s Atholl dwellings
|Construction Element||1920’s Variant||1940’s Variant|
|Vertical joints of external steel cladding||Either masked with 4in* wide strips|
or visible ‘butt’ joints 4in table (flange)
of the T stanchion exposed externally
|External corners||Exposed angle stanchions||Visible ‘butt’|
The Atholl 1945 steel house was built as follows:
- Built as semi-detached houses/ Four in A Block Flats
- Having medium pitch gable roof covered with profiled asbestos cement sheets or concrete tiles.
- Painted harled [roughcast] flat steel sheets.
- Visible vertical butt joints overlapping horizontal joints between steel sheets.
- A flat canopy was fitted above front door.
- Variant built as four in a block flats.
Foundations and substructure (1940s four-in-a-block flats)
Each steel stanchion is supported on a raised stepped plinth founded on a 2ft by 2ft by 8in (or depth to suit ground conditions) concrete pad. Around the perimeter a 12in by 4in concrete strip foundation links the stanchion base pads. A precast concrete block plinth, incorporating a lead dpc, is built off the strip foundation. The solum (oversite- the upper layers of the soil profile) consists of 3in ashes with an asphalt finish.
The steel frame consists of stanchions within all the external walls and with horizontal steel beams on the front and rear walls to support the first floor joists. Steel roof trusses complete the framework.
The frame for one half of a block which contains two flats consists of:
- Four stanchions to the gable end, of which the two 4in by 4in rolled steel angle (RSA) corner stanchions are eaves height and the two 4in by 3in RSJ I section intermediate stanchions extend to the roofline.
- Eight eaves height 4in by 4in ‘T’ intermediate stanchions, four to the front elevation and four to the rear.
- Two single storey 3-inch by 3-inch RSJ I section stanchions, located 14ft 10 1/2 inches in from the front stanchion, support a 7in by 4in RSJ spine beam which runs from the separating wall to the gable end wall.
- The stanchions have steel baseplates resting on a DPC and are bolted to the foundation pads.
- The stanchions at the front and rear walls, located at 8ft 6in centres, are tied laterally at the first floor level by 6in by 3in RSA’s fixed with cleats between the stanchions which also support the first floor joists. These angles are in turn tied to the spine beam with 3/4 inch diameter steel rods midway between the stanchions.
- The spine beam is supported at the gable end wall by a 5-inch by 1 1/2-inch RS channel bolted between the ‘I’ section intermediate stanchions.
- On the gable wall at first floor ceiling level, 2 1/2-inch by 2 1/2-inch RS angles provide support for the ceiling joists.
The roof trusses, which span between the front elevation and the rear elevation stanchions, consist of:
- 2 1/2 inch by 2 1/2 inch by 1/4 inch T section ceiling ties
- 3 inch by 2 inch by 1/4 inch angle section rafters and 1 1/2-inch by 1-1/2 inch by 3/16-inch and 1 3/4-inch by 1 3/4-inch by 1/4-inch angle section struts.
- There are no trusses on the gable or separating walls.
Cladding: The frame is clad on the outside, with steel sheets 8ft 6in wide by 3ft high and are of 11 gauge steel on the ground floor and of 12 gauge steel on the first floor. The top of each sheet is bent inwards through 90″.
The bottom of each sheet is cranked to oversail the sheet below to form a lap joint, which is secured by bolts.
The sheets are butt jointed vertically and bolted to the face of the outer flange of each stanchion.
At base course level on all external walls, a 2in by 2in angle forms a stiffener to which the ends of the steel cladding are bolted.
Lining: 2 inch by 1 inch timber fillets are bolted to the horizontal flange formed at the top of the steel cladding. 1 1/2 inch by 1 1/2 inch vertical framing is nailed to the fillets at 16 inch centres.
3/8 inch plasterboard lining is nailed to the vertical framing, with the thermal insulation being provided by means of a layer of mineral wool 1 inch thick, fixed behind the vertical framing.
The separating wall is of 4 1/2 inch brickwork lined on both sides with 1″ thick mineral wool and 3/8 inch plasterboard lining, on 1 1/4 inch by 7/8 inch timber battens.
A vertical strip of asbestos isolates the separating wall from the steel cladding at the external wall junction. The brick wall extends into the roof space, but within this area has no lining or insulation.
The partitions are constructed of 2 1/4 inch by l 1/4 inch timber studs, located at 16 inch centres, with two horizontal rails of similar size. They are lined on both sides with 3/8 inch plasterboard.
The ground floor consists of 7/8 inch tongued and grooved flooring supported on 4 inch by 2 inch joists, at 18 inch centres, and spanning from the front to the rear elevation.
The joists are supported on 6 inch by 2 inch timber bearers at the external and sleeper walls.
The first floor consists of 7/8 inch tongue and groove flooring on 8 inch x 2 inch timber joists at 18 inch centres which span from the front to the rear elevation.
The joists are supported at the external walls by RS angles and notched into the spine beam. Glass quilt sound insulation is fixed to the underside of the joists with 2 inch by 3/4 inch timber fillets.
Ground floor ceiling
The ground floor ceiling is of 1/2 inch plasterboard nailed to the underside of the timber fillets.
First floor ceiling
The first floor ceiling is of 3/8 inch plasterboard nailed to the underside of the timber joists.
The 3-inch by 2 inch timber joists, located at 18 inch centres, span from the gable-end to the separating wall and are notched into the T section ceiling ties of the roof trusses and into the RS angle at the gable wall.
The roof is clad with concrete tiles on 3/4 inch timber sarking which is supported by timber purlins of 5 inch by 3 inch section at the ridge, 6 inches by 2 inch section at the eaves and four 4 inch by 2 inch timber purlins on each side of the roof. The purlins are bolted to steel angle cleats, which are in turn bolted to the angle rafters of the roof trusses.
The chimneys are constructed of brick.
All steelwork was cleaned and painted with red lead paint at the factory, and touched up on site with similar paint to make good any damage. A paint ‘harling’ (roughcast) coat was applied to the external surface of the steel cladding sheets.
Notes for Surveyors
- Minor corrosion has stanchions at bases and at entrance to upper dwelling.
- Extensive corrosion has been observed at the edges and rear faces of the exterior steel sheets.
- Corrosion of steel fixing bolts has also been found.
Certain deterioration is specific to each Atholl variant of construction.
This is not a comprehensive list of all possible defects and equally, not all of the above defects will necessarily be present in one property. The findings above serve to highlight features that should be subjected to close examination as part of an overall inspection procedure.
It is emphasised that if significant corrosion to steelwork has occurred, the extent of deterioration may be masked by the anti corrosion products. In such cases it is difficult, if not impossible, to determine the condition of the steelwork solely by visual means.
This limits the effectiveness of purely visual inspection techniques, including the use of optical probes. If corrosion is seen to exist, the component should be exposed to enable the extent of deterioration to be determined by removal of the corroded product.
The observations reported here result from the examination of a number of Atholl dwellings on various sites in Scotland and England. Some of the dwellings were found to be in their original condition and others were in the process of being refurbished or had been refurbished.
The extent of deterioration varies considerably from house to house and site to site. In most instances deterioration of the cladding was identified, and in some cases this was severe. However, only minor surface corrosion was found to the structural steelwork, and no loss of structural integrity was observed. The extent and significance of the deterioration of steel components can and does vary from dwelling to dwelling.
Brick-clad variants; of the Atholl 1940s dwellings were also constructed at Birnam, Blair, Dunkeld
and Tullibardine, but are not included in this article.
The 2nd Atholl house report, printed below, is based on the contents of an alternative Scottish publication. We have chosen display construction detail from both publications, as they each contain important construction & build variations, due to Post-War material shortages at the time of construction.
Additionally, structural measurements below are displayed in Metric.
NON-TRADITIONAL HOUSING IN GLASGOW
TYPE: ATHOLL STEEL HOUSE (1945) BACKGROUND & DESCRIPTION
The Atholl Steel house was produced by Atholl Steel Houses Ltd., Cardonald, Glasgow, and is a modernised version of the original steel house, developed in the 1920s. After the Company put its proposals to the Second Scottish National Housing Company in October 1944, a programme of steel housing in Scotland began.
Glasgow built over 500 in the north of the city.
3400 further units; were also built in Clydebank, Dumbarton, Dundee, Eastwood, Nithsdale, Renfrew SSHA, Stewartry, Stirling.
Atholl 1945 Steel House – Frame/Base Construction.
Steel frame with external cladding of steel sheets and a painted render.
The external steel stanchions were of 100 x 100 x10 mm T-section with those on the gable walls being 100 x 75m I-section. All had baseplates bolted to the foundations.
At first floor level, the stanchions in the back and front walls were connected by continuous wall beams of a 150 x 75 x 9 mm angle section, which also supported the ends of the first floor joists. The joists were supported by a 150 x 75 RSJ which ran between gable and party walls and intermediately upon 75 m x 75mm, I-section stanchions (there were 2 to each house of the pair).
Atholl House 1945 – External Walls
To a height of 1.68 m the external cladding consisted of 10-gauge steel sheets and above this height, 12-guage sheets. The walls were lined with 10 mm plasterboard on 38 x 38 mm studs set at 405 mm CRS and fixed to the steel frame. Thermal insulation was provided by means of a layer of mineral wool, 25 mm thick, fixed behind the plasterboard.
Ground Floor; In-situ reinforced concrete with timber battens and boarding.
Upper Floor; Timber joists on boarding.
CEILINGS & ROOFS
Ceilings; A layer of mineral wool was incorporated immediately above the 13 mm plasterboard ceiling.
Roof; At Garscube; Pitched steel roof trusses were composed of angle section ties, rafters and struts.
The finish consisted of asbestos roof sheeting on roofing felt on sarking on 100 x 50 timber purlins. Rook; At Balomock; The roof finish was concrete roof tiles.
INTERNAL & PARTY WALLS
Partitions; 57 x32 mm straps at 405 mm CRS, lined on both sides with 10 mm plaster.
Party wall; This consisted of 2 layers of 75 mm clinker concrete slab walling separated by a 70 mm cavity. Plaster finish both sides.
Defects: Rusting of edges of steel sheets and spalling of render especially at gable ends and comers. Tubular steel posts at canopies in poor condition.
Possibility of slight deterioration of steel tees (frame) at foundation level.
Improvements: New external wall insulation with coloured rendering. New
profiled sheet roofing (at Garscube). Internal upgrading. New
The 1945 Atholl Steel house was in the main essentially similar to that of its 1926 predecessor, but more up to date in terms of architectural design, and improved sound and thermal insulation.