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Non Traditional Construction (Part 1)

The Laing Easiform

The Laing Easiform

 

These were constructed by John Laing builders with the first house being built in 1919. They are a fairly common form of construction – they were built by Councils in large estates as they were fairly cheap and quick to build.

We have surveyed many Laing Easiforms in both Bristol and Gloucester. These dwellings can be identified by their tall slender chimney. The chimney tends to protrude from the central wall; however these chimneys often suffer from failure of the render and tend to crack. Laing Easiforms normally have a concrete porch roof above the front door. But the main way to confirm is by entering the loft space and looking at the party wall.This is not made of brick and block as in traditionally constructed houses, but is fairly smooth and grey in appearance.

How were they built?

Surveying these types of property can be a very satisfying experience as they were all constructed in a very similar way. A solid slab foundation was laid, then a mastic asphalt floor covering which acted as a damp proof course. After the floor was dry, metal shuttering was temporarily constructed and concrete was poured into this mould. This was strengthened with reinforcing bars. As these houses are not constructed from panels brought in from elsewhere, and the work is carried out on site, these are called in-situ. Once the concrete walls were in place, the shuttering was removed and the roof could be added. Normally a traditional cut-type roof was used with some bolted trusses to add strength, for instance those found in Brentry. A flat thick roof comprising a concrete slab was sometimes used, such as in Lockleaze.

What are the associated problems?

Laing Easiforms were not considered to be defective under the Housing Act and as a result can be mortgageable. Hence they are one of the few types of non traditional construction where a mortgage may be obtained! But With every rule there are the exceptions and the most common is the pre 1940’s Laing Easiform. Their construction had thinner walls, with 3” of poured in-situ concrete,  a 2” cavity and then a 3” inner skin – which is very thin by any standard. Some of these are still present in Lockleaze in Bristol and these are seldom mortgageable. The post-war properties were of  thicker walled construction, with  3 ½ ” concrete, a 2” cavity and a 3 ½” inner wall,  such as many of those found in Bishopsworth.

When we survey a Laing Easiform, one of the obvious problems is corrosion of the embedded metal. This is often characterised by horizontal cracking along the reinforcement lines. This may be repaired cost effectively depending on the extent of cracking that is apparent. It is a subjective call as to whether the extent of cracking is cost effective to repair; most suffer some level of cracking.

The other commonly occurring problem is the quantity of asbestos that is often used in the construction.For example, the soffits were originally of asbestos cement boarding, which has often been hidden by new UPVC. The loft hatches were again asbestos boarding, as were the under stairs cupboards. Many of the ducts and boxings-in were also cement type board and thermoplastic tiles were often used to finish the floor.

 

Pitched Roofs

roof

Pitched Roofs

Roof repairs can be very expensive, not just the materials and manpower, but will possibly require scaffolding as well. So take binoculars or a camera with a powerful zoom to enable you to visually inspect the roof covering.  You can do this at any time, without the agent having to be present. As always, look at the neighbouring roofs see if they have recently been re-covered, a good indicator of when yours will need doing.

What is the roof covering ?

Next, focus on an individual tile and try to determine what it made of, clay (older) or concrete (more recent). In some areas, older properties have real slates. Concrete tiles indicate a post-war roofing replacement. Is there anything special or unusual about the type of roof tile? Some tiles such as Triple Deltas and Bridgewater tiles are not as readily available as more common types such as Pantile or Double Roman.Hence they are more expensive to repair or replace.

Can you see any defects?

Are there any slipped or missing tiles? These indicate a lack of routine maintenance but also water ingress is very probable.  Water can cause damage in a timber loft space which can be very expensive to repair! If there is some lighter colouring of the surrounding tiles, this may indicate a more recent break or slip.

Is the roof a “patch work quilt” of differing colours of tiles? Probably someone has made many repairs and it may be time to replace the roof covering completely. Also, look out for small grey tags known in Bristol as “tingles”; these metal (usually lead) clips are used to secure individual tiles and they indicate localised repairs have been carried out. If you see any grey coloured tape, this is normally called ‘flash band’ and is used as a temporary repair. However, it is simply a sticky tape and cannot be considered permanent – the defect should be properly repaired, not just taped over!

Can you see any ‘lifted’ tiles, ones that are not lying flat? If so, there could be a problem with the roof structure beneath. Where the property is in an exposed elevation, the tiles may be vulnerable to lifting by wind and regular repairs will probably be required.

If there are a great many slipped tiles, possibly the roof is suffering from ‘nail fatigue’; the nails have started to rust away and can no longer hold the slates in place.Although such failures may occur in a localised area initially, it is highly likely to occur more widely in the near future.

Man-made regular roof ‘slates’ can be asbestos containing. They are fixed centrally with a single nail and may start to ‘ cup’ or dish. When this happens, the life span of the roof covering  becomes  very short.

Get an overview of the roof structurally

Finally, try to check the structure. Look at the condition of any mortar such as along the ridge or the hips. If the mortar is missing, this indicates lack of routine maintenance.These areas will require repairs at the very least and possibly more extensive remedial action.

Is there any ‘dishing’ to the roof covering?Do the tiles lie in a straight line? If not, this suggests an inadequacy in the roof structure beneath, possibly very costly to remedy.