Problems with Non-Traditional
House Construction

We are independent building surveyors, free phone us for help and advice

We can provide help and advice with regard to building surveys, structural surveys, independent valuations, property surveys, structural reports, engineers reports, specific defects report, home buyers reports or any other property matters . We have carried out surveys on many different types of non-traditional construction.

Please free phone 0800 298 5424 for a friendly chat with one of our surveyors.

non-traditional house

What is non traditional construction

This is a system build which effectively means the building is built on a structural frame and clad. There are many different types of non traditional buildings such as:

1. Metal frame

2. Concrete frame

3. Timber frame

4. Concrete panel construction

5. Structural insulation panels

6. In situ concrete

7. One-offs

non-traditional house

Non traditional construction

Many non traditional construction houses were built after the Second World War to meet the needs and demands of the population at the time. This immediate need for a large number of houses meant that the Government had to look at how they constructed houses and moved towards more factory type processes. Indeed some of the factories that carried out the work, it is said, had been making aeroplanes and bombs for the War one week and then changed to building/manufacturing houses the next week; we don't know how true this is.

Other surveying articles that may be of interest

We have written many surveying articles which may be of interest to you:

The history of non-traditional building
Different types of non-traditional housing
Non-traditional properties, what are they?

BISF House

One of the more common types of non traditional construction houses is the BISF house, which stands for British Iron and Steel Federation. The original construction of this type of property consists of a structural metal frame and a roof truss construction of tubular metal with a shallow pitched asbestos roof, and profile metal sheets at high level with brick or render at low level.

non-traditional house

Originally the property would have
had profile metal cladding

There were various different types of these houses; this looks to be a type A1 built between 1944 and 1950 of which there were approximately 35,000 built. Over the years many non traditional properties have been altered as in the case of the adjacent photograph where vertical tiling was added to the first floor and a rendered extension to the ground floor, although it must be remembered that they are still a non traditional construction underneath.

non-traditional house

Vertical tiling added to first floor and
rendered extension to ground floor

Problems with non traditional construction houses

The Building Research Establishment often known as the BRE are generally considered to have carried out the best research on this type of construction and have identified the following problems:

1. Minor to severe corrosion of the rolled steel angle (RSA) and rolled steel channel (RSC) stanchions, particularly at the bases and the corners.

non-traditional house

Example of tubular metal frame within
the roof of a metal framed property

non-traditional house

Example of rusting that we have seen
in the roof of a metal framed building

2. Minor to severe corrosion of the sheeting rails

3. Cracking of ground floor slabs, particularly at the corners

4. Corrosion of metal lathing and failure of render

5. Corrosion of profile steel sheets and steel flashings

non-traditional house

Rusting to profile metal cladding


6. Corrosion of cast iron flue pipes and metal cowlings

non-traditional house

Rusted metal flue

7. Deterioration of profiled asbestos cement sheet roof covering


There are always limitations to a visual inspection and you can only see much of the above problems by physically opening up the structure.

non-traditional house

Deterioration to asbestos roof

Is the Structural frame sound?

The risk with buying any steel framed property is if the structural frame is sound or not. The only way to see this is by opening up the structure which we are willing to do but obviously you do need to get permission from the existing owners and also ensure that you have a builder who can put back the openings to a satisfactory standard.

In our experience key areas are generally at ground level, first floor level and roof level where the steel frame is joined together which should be checked for rusting. This could be caused by water discharging onto the base of the property to condensation in the higher level steel frame.

non-traditional house

Metal frame, purlin and metal truss

Mortgage companies won't lend on non-traditional houses

One of the interesting facts is that many mortgage companies won't lend on non traditional houses. As the vast majority of people buy properties with mortgages it limits the market you can sell into. We would add further that their lending criteria changes from time to time which does mean they will lend on them some of the time and then not lend on them.

Non-traditional houses, can they be made into mortgageable houses?

Some companies do specialise in carrying out work to non-traditional houses to make them mortgageable. We have however found that where the neighbouring property does not join in with this work there will still be an adverse affect on the property and the property value.

Experienced surveyors

It is important that the surveyor knows what they are looking at. We once had the privilege of teaching student surveyors and became very aware very quickly that they may well be looking at a problem but not seeing the problem. This too can be true of qualified surveyors who come in lots of different shapes and sizes, with lots of different knowledge levels and experience.

In particular we have been called in several times to do Building Surveys where the owners have not known that the type of construction is non-traditional construction even though they have had a mortgage company valuation. Unfortunately this is due to a lack of knowledge and experience with mortgage Valuers. After all, valuation experts are not building construction experts.

Don't be fooled by how the building looks

Over the years many non traditional houses have been altered, extended and amended with cladding, vertical tiling, render, etc so they do not necessarily look like a non traditional construction. Please be aware that even though they look like a traditional property they are still a non traditional construction and therefore may be unmortgageable.



This property has had pebbledash render in parts as well as plastic cladding and extensions but remember the main part of the building is still a metal frame

non-traditional house

Pebbledash render

Plastic cladding

Plastic cladding is another way of changing the look of non traditional properties.

non-traditional house

Plastic cladding has been added to
the top of property

non-traditional house

Close up of plastic overcladding


Vertical tiling

The photograph below shows a building which would have originally had profile metal sheeting to the upper parts which has now had vertical tiles added. Vertical felt tiles can also be used as shown below.

non-traditional house

How vertical felt tiles sit around the

non-traditional house

Vertical felt tile

non-traditional house

How vertical tiling and new windows
can considerably change the look of a
property but underneath it is still a
metal framed building

Even a profile metal roof can look like a tiled roof

To the inexperienced eye a profile metal sheet roof can actually look like a tiled roof.

non-traditional house

Close up of edge of profile metal
roofing that looks like a tile

non-traditional house

Weathering effect to roof

non-traditional house

Rivet where you can see roof is
riveted together


Asbestos was a common popular material which was used almost as commonly as wood. In non traditional construction houses it formed the roof material and it also generally formed such things as the fascias and soffits and the gutters and downpipes.

non-traditional house

Asbestos house that we surveyed

non-traditional house

Asbestos house

The sketches below show typical areas where asbestos can be found in non traditional properties.

non-traditional house

Asbestos - outside

non-traditional house

Asbestos - inside

We would add that we are not asbestos surveyors and t he only way to be certain all asbestos has been removed is to have an asbestos report carried out.

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