Weir Multicom

The Weir Multicom system was developed by Weir Housing Corporation Ltd, Lanarkshire in the late 1960s.

Built as Bungalows and 2-storey semi-detached and terraced houses. Having a shallow or medium pitch gable roof covered with concrete tiles.
The Weir Multicom system was a Scot­tish system, designed for the build­ing of one or two storey detached, semi-detached and terraced houses in 2, 3 and 4 bedroom configurations.
The range of designs included L-shaped houses (as shown above) and standard rectangular designs. The system is based on 16 inch modular storey-height timber framed wall units and prefabricated floor panels which could be assembled in various combinations. There is some ambiguity as to the total number of dwellings built, with reports varying from between 600 and 4,500 dwellings being built between 1974 and 1976.

The system was designed to be completely flexible, enabling components to be used for new designs in an almost unlimited variety of house plans. This provided architects with a wide variety of scope as this system could also be combined with traditional forms of building.

The foundations are generally of precast concrete post and beam construction or of brick. (Some properties have been found to have concrete strip footings supporting 4 1⁄2 inch brickwork perimeter and internal support walls. An underfloor depth of about 10 inches with an oversite cover of concrete. An underfloor space ventilated by 10 double airbricks).

The external walls are generally timber framed to a 16 inch planning module. The external cladding is generally of coloured aluminium sheeting, which is bonded to 3/8 inch hardboard, which is a system of construction that was extremely popular in the United States and Canada at the time of construction. Other materials such as cedar boarding, asbestos sheeting, tile hang­ing and brick veneer could also be used on the outside of the walls.

The external storey-height timber frame panels have 3 inch x 2 inch studs, spaced at 16 inch centres, and sheathed externally with 3/8 inch high-density oil-tempered fibreboard. The panels are separately clad with screw-fixed, enamelled, rolled 22 swg aluminium sheets, with vertical ribs at 16 in spacings to provide separation from the sheathing and allow back-ventilation. A 1 inch-thick mineral wool quilt was applied to the frame cavities, the continuous paper side tabs being stapled to the inner face of the frames. A layer of polyethylene sheeting was used as a vapour barrier, with the internal leaf, which consists of 1/2 inch plasterboard, on the inside.
The aluminium alloy is of 0.021 gauge sheet and is anodised and then stove enamelled to give a hard, non-fade colour finish.
The U-value of the walls at the time of construction was claimed to be 0.15 B.Th.U/hr sq ft deg F.
External modular wall panels were constructed in 1M, 2M, 3M, 4M, 6M, 8M and 9M panels which equates to widths of 1ft 4in to 12ft with composite panels being made in widths up to 17ft 4in. All units are 7ft 7 1/4 inches high for the upper floor and 8ft 9 inches for the lower floor. The panels were produced either solid or with openings containing pivot hung windows with the option of double glazing if required. Down­stairs wall units were made to incor­porate external doors, the opening being formed in a 4ft-wide (3M) panel. In general all units have vertical studs spaced at 16 inch centres and there are, in addition to top and bottom rails, four strengthening rails.

Internal partitions are also of timber-framed construction. These are of two basic types, these being loadbearing and non­loadbearing.
-The framing of loadbear­ing partitions is at 16 inch centres
-The framing of non-loadbearing partitions is at 24 inch centres.
Each type has 1/2 inch plasterboard cladding on both sides.
Door panels with openings framed for standard door sites could be readily fitted to these panels.

Party walls are of a lightweight con­crete core, which has a loadbearing insulated timber framework on either side. The internal surface also consists of 1/2 inch plaster-boarding.
Floors are of stressed skin construction to obtain the maximum clear span, e.g. by using 7 inch by 2 inch joists at 16 inch centres and a decking of 18mm flooring grade chipboard, a clear span of 17ft 4 inches can be achieved.
Standard floor panels are 4ft wide. The length and depth of joists is controlled by design requirements. Plywood flooring that is 2 inches thick, could also be used for stressed skin panels.

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Several types of roof were made with some using prefabricated roof trusses. In the standard range, designs were for 5 degrees pitched roofs, clad with Galbestos roof decking which was carried on timber purlins, spanning between crosswall frames and set into prespaced pockets in the frame spandrel.
Galbestos was ex­tremely effective in neutralising drum­ming noises from heavy rain and hail­stones. It consisted of a steel core which was coated with zinc. Bonded onto this was an asbestos felt coating with a coloured poly­ester resin finish which provided a wear surface.

More traditional roofs were also constructed to take a standard tile finish. These roofs had a 22.5 degree pitch and consisted of either a simple spar and ceiling joist truss, sup­ported in timber crosswall beams or flush-faced timber roof trusses which were connected with metal plate con­nectors, suitable for assembly on automated machines.

All units are light enough to be easily manageable. Houses erected by this technique were weatherproof already by the second day and could be erected, ready for occupation, by six men in 10 days. It was considered that these times could still be improved upon further as installation techniques advanced further. The total weight of the house was about 14 ton, and noise insulation, at the time of construction was claimed to be within the statutory standards required for party walls.

Variants
Timber frame panels sheathed externally with plywood overlaid with breather membrane and separately clad with brick throughout, or to first floor level with tile hanging on timber battens above.
No polyethylene vapour control layer in roof space.

Internal fittings

All plumbing was fitted internally and the main pipework was carried in a central duct running from floor to roof. The hot and cold water piping was of copper, whilst soil, waste and rainwater pipes were of PVC. The standard central heating system for the houses was ducted warm air.

Performance in use
Upon inspection of a small number of dwellings the Weir Multicom dwellings were found to be in a fair condition and free from signs of structural distress. Exposed timbers in the internal walls, floors and roof was found to be generally sound and dry. However, localised areas of decay was identified in the chipboard flooring of the kitchen and bathrooms, which was presumed to have been caused by a number of factors such as persistent water leakage and occupant spillages.

Internal partitions are also of timber-framed construction. These are of two basic types, these being loadbearing and non­loadbearing.
-The framing of loadbear­ing partitions is at 16 inch centres
-The framing of non-loadbearing partitions is at 24 inch centres.
Each type has 1/2 inch plasterboard cladding on both sides.
Door panels with openings framed for standard door sites could be readily fitted to these panels.

Several types of roof were made with some using prefabricated roof trusses. In the standard range, designs were for 5 degrees pitched roofs, clad with Galbestos roof decking which was carried on timber purlins, spanning between crosswall frames and set into prespaced pockets in the frame spandrel.
Galbestos was ex­tremely effective in neutralising drum­ming noises from heavy rain and hail­stones. It consisted of a steel core which was coated with zinc. Bonded onto this was an asbestos felt coating with a coloured poly­ester resin finish which provided a wear surface.

More traditional roofs were also constructed to take a standard tile finish. These roofs had a 22.5 degree pitch and consisted of either a simple spar and ceiling joist truss, sup­ported in timber crosswall beams or flush-faced timber roof trusses which were connected with metal plate con­nectors, suitable for assembly on automated machines.

All units are light enough to be easily manageable. Houses erected by this technique were weatherproof already by the second day and could be erected, ready for occupation, by six men in 10 days. It was considered that these times could still be improved upon further as installation techniques advanced further. The total weight of the house was about 14 ton, and noise insulation, at the time of construction was claimed to be within the statutory standards required for party walls.

Variants
Timber frame panels sheathed externally with plywood overlaid with breather membrane and separately clad with brick throughout, or to first floor level with tile hanging on timber battens above.
No polyethylene vapour control layer in roof space.

Internal fittings

All plumbing was fitted internally and the main pipework was carried in a central duct running from floor to roof. The hot and cold water piping was of copper, whilst soil, waste and rainwater pipes were of PVC. The standard central heating system for the houses was ducted warm air.

Performance in use
Upon inspection of a small number of dwellings the Weir Multicom dwellings were found to be in a fair condition and free from signs of structural distress. Exposed timbers in the internal walls, floors and roof was found to be generally sound and dry. However, localised areas of decay was identified in the chipboard flooring of the kitchen and bathrooms, which was presumed to have been caused by a number of factors such as persistent water leakage and occupant spillages.

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Google Street view Weir Multicom Houses

In 1974, the services offered by the Weir Organisation relating to industrialised housing was as follows:
(1) The ‘package deal’ covering the initial survey, the preparation of layout plans, the laying of sewers, the formation of roads and the supply and erection of houses either from the standard range or from designs based on the standard range of components.
(2) The supply and erection on a serviced site of houses either from the standard range or from designs based on the standard range of components.
(3) The supply only of either standard houses or houses based on the range of components to a contractor nominated by a local authority.
(4) The supply of standard components for incorporation in other building systems, including traditional building, and the design and manufacture of special components where the order is large enough to justify setting up special production facilities.