Atholl Steel Framed House 1945 Variant
- Manufacturer: Atholl Steel Houses Ltd
- Period Built: 1945-48
- Number Built: 1600
History 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.
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 subsequently approved an order for a further 1500 houses which were built in 1947.
Research indicates that it is likely that all of these 1945 Atholl houses were erected as four in one blocks. A pair of semi detached houses would be split into 4 flat type, individual apartments with front and side access to ground and first floor levels respectively.
By early 1948 the supply of steel declined drastically. The Cabinets 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 an modified version of their design which retained the inner steel frame but instead used 100mm brick 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 framed house 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 Atholl 1945 house was built as follows:
- Built as semi-detached houses.
- 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.
Frame: 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 roof line.
- Eight eaves height 4in by 4in T intermediate stanchions, four to the front elevation and four to the rear.
- Two single storey 3in by 3in RSJ I section stanchions located 14ft 1O 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 base plates 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 RSAs 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 in 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, each 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 in 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 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 bolting.
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 in 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 mineral wool 1 inch thick 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 roofspace 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 of steelwork has occurred, the extent of deterioration may be masked by the 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.