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.


Non Traditional Construction (Part 3)

PRCs, Cornish Type 2

The Cornish Type 2

Unlike the Cornish Type 1 PRC houses that are found all over Bristol, the Type 2 does not have the distinctive mansard hipped roof, clad with vertically hung tiles on the upper floor. It has ‘normal’ vertical walls! Type 2 houses can be found in and around Stoke Gifford. However they are not always recognisable. Both Cornish systems were declared as “defective” under the 1985 Housing Act and many were subsequently ‘repaired’.When Type 2s have been “bricked up” or clad with either brickwork or render finishes, they appear to be of standard Council 1950’s style construction. In their original form, the concrete reinforced panels are larger than those used on the Type 1 Cornish.

Some mortgage lenders are still wary of PRCs; for further information, see www.BritishCouncil of mortgage lenders etc.

 What are the problems with the interiors?

The internal partitions were not always the standard timber studwork expected in traditionally constructed properties. They are often a lot thinner.Partitions are around 120mm thick in a traditional type property, compared to 75mm in the Cornish Type 1. The latter were often made of paramount boards and if opened up have a segmental carboard type structure internally. These were poor sound insulators and very hard to fix things such as pictures to.

Where the property has been ‘bricked up’ (overclad),the  floorboards are often loose around the edges of rooms. The support joists have lost their bearing  on the external walls due to the rebuilding work. Hence where they meet the wall, the ends of the floorboards often are poorly supported and “bounce” as a result.

And most non-traditionally constructed properties of this time contain asbestos. Products oftencontaining asbestos are the soffits, thermoplastic floor tiles and the in-built soil stack. This is not readily visible except where it is peeking through the roof. Also Artex™ ceiling coverings, often as a result of the 1980’s fashion to hide cracked ceilings.

What about the services?

As these types of property are generally in Council/ Local Authority estates, they may not have been updated.  Electrical checks and gas checks are strongly advised. Due to the solid concrete spine wall, the electrical services are often in trunking as opposed to set into the walls.

These houses will most likely have the older lead water service pipes which can pose a health hazard. They are set into the solid floors and can leak unnoticed for prolonged periods of time, often resulting in insurance claim. We have helped progress many of these in the past!

Recent developments

There has been a drive in the last year in South Gloucester by Merlin Housing Association to overclad some of their Cornish type 2 Units. We have acted as Party Wall Surveyors to some of the adjoining owners. The tenants have made very favourable comments with regards to reduced mould growth and decreased fuel bills since the external wall insulation has been installed. The only complaint has been that handrails and satellite dishes have required special fixings to go through the insulation and fix onto the concrete beneath.

We should be well versed in their construction as our Surveyor Jon Holloway and his family live in one!

Non Traditional Construction (Part 2)

PRCs, Cornish Type 1

What’s a PRC?

PRC stands for ‘PreCast Reinforced Concrete’. The drive for more cost-effective ways of building house began before WWll. So a number of ‘system built’ homes were constructed in the Thirties. However, the war caused huge skilled labour shortages along with was a surplus of steel and aluminium production.  As a result, many new varieties of prefabricated concrete (in both pre-cast and in-situ forms), timber framed and steel framed systems emerged. Between 1945 and 1955, around half a million homes were system built. That was about 20% of the new housing stock! And a further three quarters of million between 1955 – 1970.

What’s the problem?

When the panels were cast originally, either off or on site, the metal reinforcements were embedded in the concrete. Concrete is a highly alkaline material and offers protection to the embedded steel.

However the carbon dioxide in the atmosphere,  carbolic acid in rainwater and chlorides in the original concrete can mix. Over time, this can affect the composition of the concrete. The concrete undergoes a chemical change called carbonisation. The metal reinforcements in the panels and supports then become less protected and the metal can corrode. When the metal corrodes it will expand and cause the surrounding concrete to crack and fail. This can be readily seen in concrete fence-posts in gardens which fail and expose the rusted metal reinforcements.

These failings were highlighted in the 1980’s, when such Council housing came onto the private market. This often meant that mortgage companies would refuse to lend on PRC properties. The government then stepped in and many of these systems were declared as “defective” under the 1985 Housing Act.

The government then set up a company to license “repairs” of these properties. This involved stripping out the old concrete and replacing it with brick and blockwork. This was often done whilst the occupants were still in-situ. This type of work was expensive, but it gave the house a PRC Certificate. This enabled mortgage lenders to consider the property as suitable for lending against. It should be noted that if an adjoining property has not been “repaired” this can also be grounds for a lending companies Valuer to refuse a mortgage so look at the neighbouring properties as well.

The Cornish Type 1

One of the most instantly recognisable PRCs is the Cornish Type 1. This has a distinctive mansard hipped roof, clad with vertically hung tiles on the upper floor.A mansard roof has sloping sides, each of which becomes steeper halfway down. The Type 1 looks a bit like a bungalow but withdormer windows around the first floor!

Thirty thousand Cornish 1 & 2 units were constructed in England over a 20 year production run. They were made by the Central Cornwall Concrete & Artificial Stone Co. Many are a distinctive part of the Bristol landscape and they can be seen from Chipping Sodbury to Long Ashton. The Type 1 was particularly common in Brentry, Thornbury,Patchway and also in Little Stoke.

Both Cornish systems were declared as “defective” under the 1985 Housing Act and many were subsequently ‘repaired’.  However, over 30 years after this legislation, we still see many units that are in their original condition, especially in Patchway.

What repairs are usually required?

Common issues are the joints where the soil vent pipe penetrates through the roof covering this is a design issue and normally remedied by better flashing around this joint and is normally noticeable by staining of the ceiling in the Bathroom.

These suffer badly from poor thermal performance of the first floor which can lead to mould growth. The original insulation in the Mansard type roof was notoriously thin at around 25mm in thickness, which is very minimal and if improvements have been made they are often only visible using a thermal imaging camera.

As with most PRC properties asbestos was also used in soffits and floor tiles and roofing of the outbuildings.


Asbestos Boarding

asbestos boarding


Asbestos Boarding

Asbestos boarding is one of the harder materials to ascertain visually what type of asbestos may be present.
Cement boards, (normally white) are often harder and more brittle.
This type of intrusive testing must ONLY be carried out by a competent person as this can be very dangerous.

Asbestos boards tend to flex slightly before shearing.

With boarding it is essential that tests are carried out as this is one area where the more harmful Blue and Brown fibres can be found.


During the course of our inspections we often note external boarding on properties that we presume contains asbestos until proven otherwise.
Due to its hard wearing nature cement type boarding was often used in soffits. This was very common in properties from the 1950’s through to the 1980’s.
Often these have simply been clad with UPVC and only come to light when say the UPVC has been disturbed by adverse weather conditions.

Infill panels in walls are also fairly common mainly in 1970’s buildings due to their good fire resisting properties.
We have even seen it neatly stacked in sheds or next to fences or hidden out of site as mentioned in our previous blogs.
We have also found it cut and shaped as decorative finials externally which would have created a lot of dangerous dust when installed!


Asbestos sheeting was often used internally for lining loft hatches, creating boxing in and as boarding on walls and ceilings.
This type of material is often painted many times in its life so has a simple gloss finish which makes it harder to recognise.
You can use a bradawl or Stanley knife to make a small nick in the surface to look at the material beneath.

The other great visual indicator is a dimpled almost golf ball effect that makes it stand out as being a manufactured board as opposed to timber.
These boards are often found beneath staircases or making the under stairs cupboard.
Where pipes run internally these are often boxed in again sheet material is used.
We have also found sheets of asbestos insulating board used to support tanks and cisterns in loft spaces.

What to do

Boarding can be composites of asbestos including the more dangerous blue and brown fibres sometimes called mill boards. It is imperative that when boarding is found and is suspect that it is tested by a competent operative preferably an independent surveyor with no affiliation to removals companies to insure that there is no commercial interest in the findings.

Asbestos Pipework

Asbestos Pipework

Asbestos was often used to strengthen cement based pipework. This pipework performs fairly well as long as it has been regularly decorated throughout its life span. However, where paint has failed the cement based pipework will be exposed and can spall or become porous.

Gutters and downpipes were very often constructed from asbestos cement. The condition of them gives the key to removal, remember they cannot be rubbed down and repainted unlike cast metal gutters if they require decoration.You must not sand or scrape the existing paint from the surface as this can release fibres. They are brittle and if used below ground are susceptible to compression forces causing them to crack although this often cannot be seen. Even when replaced it is unlikely that the ground has been excavated and even where the visible pipework has been removed it is often sealed to a below ground cement pipe which is still asbestos containing.

Soil pipes sometimes called soil stacks are used to take foul water from bathrooms and WC’s .It is easily identified as it should extend above the height of windows or lower roof line and is open at the top (sometimes covered by a cowl) to allow air to enter the stack it is normally wider at around 6” or 150mm in diameter. These can also be cement type pipework.

There are often mushroom shaped cowls extending through walls from where old boilers were located and removed. These are fairly easy to identify as they are often short in length and curl upwards with a domed top and they are highly likely to be asbestos cement.

It is very hard to determine if pipework is cast metal or cement based, especially when it is painted as often the connectors and fixings appear visually the same. With open hoppers curved edges can be a good visual indicator as cast metal is not easy to shape in curves hence if the hopper head is scallop shaped then it is likely to be asbestos cement based. A good way to determine if the pipes are cast metal or cement based is to use a magnet as shown in this video.However with all good tests there is always an exception to the rule and this is zinc guttering which is not magnetic but not asbestos containing.

Often flue pipes to boilers are left inside properties these are likely the most dangerous as they can contain Blue or brown asbestos and should be tested prior to removal.

If you are removing them or employing a trained competent contractor then Health and Safety Executives “Asbestos Essentials” gives an idea of what is required to safely remove these pipes.


Thermoplastic floor tiles

Thermoplastic floor tiles

Thermoplastic floor tiles are still very commonly found in 1930’s and later properties. These are often in multi-coloured combinations. They may be red, green, blue, yellow or black; one manufacturer Marley in the 1940’s and 1950’s offered over 20 different colours. These used to be advertised  with the wonderful slogan  “ Marleytile™ – for exciting, colourful floors”. However, they are likely to contain asbestos fibres. When testing, we have to test individual colour types separately, so with (say) a black and red pattern, two tests are required.

Where are they found?

They arestill being walked on in many local authority properties but are regularly inspected!  They are often hidden beneath floor coverings andmay be visible if floor coverings are loose.  Or look under the stairs – this areais often overlooked when new flooring is laid or a latex levelling screed is applied.  They are most likely to be discovered whenremoving  a floor covering.

It is a common misconception that these tiles are only bonded to solid ground floors. We have found these on suspended timber floors – and recently throughout the first floor beneath the bedroom carpets of a Fishponds property.

When bent in testing, the thermoplastic tileoften makes an audible noise and snaps. By contrast, the very common lighter coloured vinyl-based tiles seem to bend and are much more flexible.

Bitumen Bond

The black tarry bitumen used to bond the tiles in place can also be asbestos containing. Hence when tests are carried out, it is vital that the black tar beneath is also tested as well.  We have had cases where tiles are asbestos containing and the adhesive is not and vice versa.

These floor tiles are considered one of the least risky asbestos-containing materials  to remove. The fibres are often very well fixed in the matrix of the materials and the asbestos content is often less than 1%.  However removal of the bitumen if found to be asbestos containing is very hard.It has to be skilfully removed from the surface of a solid floor, sometimes called “scrabbling”. With timber flooring it is often easier to simply replace the floorboards than to try to remove the adhesive.


Garage Roof

Corrugated Cement Sheets

The word ‘Asbestos’ strikes terror to many clients’ hearts – and the separate garage roof is often a principal culprit. Roofs covered with corrugated cement sheets are very likely to contain white asbestos. The corrugations may be “Big 6” or “Little 3”, which refers to the size of the gap between the ridges -in inches ! So they date from pre-metric times – but  asbestos has been used in building materials since the early twentieth century.

These are normally found on a 1960’s concrete sectional type garage.  These are simply constructed from posts into which the concrete panels are slotted, forming the walls. Then  metal trusses form the support for the corrugated sheet asbestos roofing. The Health and Safety Executive have a work sheet detailing how to safely remove asbestos cement; this will give you an idea of what is involved.

What condition are they in?

Asbestos sheets are not necessarily ‘dangerous’ if they are in good condition. They were expected to have a life span of around 25 years. However many of the sheets have easily doubled their expected life span and are still going strong. If the sheets are in sound condition, then sealing them properly may be a viable course of action rather than removing them. Remember surveyors do pick up on corrugated sheeting if you are selling a property so you would need evidence that the sheets had been treated correctly.

What about removing them?

Such work has to be undertaken by a specialist contractor. While there are several types of asbestos, most companies don’t even test corrugated sheets of this type on a garage or shed. They simply remove them presuming they contain white asbestos.

When pricing for removal, don’t forget to allow for replacement of the roof covering with new sheeting! There are boards available that are similar in appearance but stamped “NA” meaning no asbestos. You can use the lightweight black bitumen based Corolux style sheeting or PVC sheets, although these will have a reduced life span.

What about other asbestos hazards?

Garages may also contain blue or brown asbestos in their make up – or

there may be sheets of boarding left lying around, normally leaning against a garage and hidden by undergrowth. We have come across many situations where the garage structure is not presumed to contain asbestos; however when we have visited the site, we have found numerous boards of differing ages. These have been collected and stored in corners as they “may come in handy at some point”.These however should be tested as they can be the more dangerous blue and brown types and only testing will identify it. If blue or brown asbestos is found to be present, this will increase the cost of removal.

We have also come across situations in either sheds or garages where the material used is clearly not wooden fibreboard, orientated strand board or chipboard. This is obvious from its brown colour or textured surface finish. Then it should be presumed to contain asbestos and again should be tested.

Artex Ceilings


Artex Ceilings

When we are carrying out surveys, one of the most common things we note as a ‘potentially asbestos containing material’  is Artex™. The brand name Artex comes from combining the words artistic and textured. This  textured coating  was applied to many a ceiling or wall in both residential and commercial properties the length and breadth of the country. It became particularly popular from the 1970’s onwards. Artex is still readily available from most DIY shops.

What is Artex used for

Artex is used to hide older cracked lath & plaster ceilings. It reduced the need to skim a ceiling in quickly constructed 1980’s houses. It was very much in fashion and produced perfectly acceptable ceilings mainly with the familiar stippled and swirled patterns that didn’t require plastering skills. So the owner could ‘keep up with Joneses’!  It was also applied to walls in the same fashion. However, it is very difficult to match the pattern when trying to repair it.

The Issues

There is a lot of differing information as to when asbestos stopped being used in Artex as a strengthening fibre. Some say it was banned in 1985, some say it was 1999. This may be due to the dates on which different types of asbestos were made illegal to be used in the UK. This reflected the differing natures of blue and brown asbestos as opposed to white. We have sampled ceilings post 1985 and white asbestos was shown by laboratory analysis.

In the last few months, Bank Valuers have been noting the presence of Artex during the basic level valuation survey. Although they have stopped short from requesting that it be tested, they have recorded it. Some experienced Estate Agents are also bringing it to the vendor’s attention when visiting the property to value it for sale purposes.

For many years insurance companies have taken the presence of Artex very seriously and insisted that all Artex pre 2000 be tested for asbestos content when an insured peril has occurred.  For example, when Artex ceilings or walls have been damaged by a leak from a pipe or sanitary ware or rain water ingress.

What to do about it?

If Artex is present in your home already it does not necessarily pose an immediate and dangerous hazard. Is it in good condition and well sealed (i.e. painted) ? Then even if it is asbestos containing, the fibres are bound up in the matrix of the material and painted surface.

It is most likely to be disturbed during refurbishment works, for example  general improvements such as lighting or fixing to ceilings.  Leaks or other insurance related accidents, moving walls or adding Extensions can also damage it.  If it is in sound condition, then the easiest course of action is to leave it in place. It is also possible to seal the Artex with PVA glue and skim over the top, depending on the thickness of the pattern. This can be termed ‘encapsulation’ and you should document any such work in detail so future occupiers understand not to disturb the coating.


The A Word

The A word

What is Asbestos?

When you are in the process of buying a house, the A word is one of the scariest you can hear. This is due to the culture of fear that surrounds the subject. There are still a large number of deaths that occur as a result of historic exposure to the material.

Asbestos is a naturally occurring mineral that was mined in Canada and South Africa. It has been used for centuries as it has amazing qualities as a good insulator with extraordinary fire resistant properties .It was regarded for a long time as a wonder material that had so many differing applications from ironing boards to Christmas decorations. It is our intention to run a short series of blogs, over the next few months, on the use of asbestos in buildings. If you have any concerns over a property you are looking to buy and you need to have samples taken and tested, Domestic Sampling is able to provide an independent service, incorporating analysis by UKAS laboratories, all for as little as £75.00.


Types of Asbestos

There are many kinds of Asbestos but in UK construction we mainly refer to Blue (Crocidolite), Brown (Amosite) or White (Chrysotile).

Blue and Brown contain amphibole fibres that are small, harpoon like needles. They can be released when materials are abraded, damaged, broken or drilled. These cause greatest concern when found, as they present the most danger to health and thus the most serious financial implications for removal. If the contaminated area is over 1m2 then the Health and Safety Executive must be informed and a Licensed Contractor should be used for its removal. There are a limited number of contractors available to do this specialised removal and all their operatives must be well trained. Inevitably this work will prove costly. The use of Blue and Brown Asbestos was banned in the UK in 1985. It is most commonly found in industrial environments, for example Asbestos Insulating Boards (AIB) and pipe lagging.

White Asbestos contains serpentine fibres that are longer and more flexible in nature and they to are normally only released during abrasive or intrusive contact with the material. This type of fibre was normally used to strengthen other materials and to provide fire proofing. It is normally bound up tightly within the material it is a component in, such as corrugated sheets, boards and Artex ceiling coatings. These require a Competent Contractor as opposed to a Licensed Contractor for removal. To qualify as such requires an intensive training course and the acquisition of the appropriate insurances and disposal certificates. The use of White Asbestos was only banned in the UK in 1999 which gives an indication of the level of risk ascribed to the differing materials by the Health and Safety Executive.


Under The Floor

What is lurking under those floorboards ? Ask a robot –

All sorts of nasty surprises may lurk beneath the floor boarding! Wood boring insects, dry rot, wet rot and vermin infestations for example. The spaces underneath the ground floor of properties are  rarely accessible. However, some houses we visit will have loose floorboards which we can lift, normally beneath the stairs. Sometimes behind the front door is a hatch, often secured by just a few screws.This gives access to the stopcock which is often located inside the front door and also to the space below the floorboards.

How can technology help?

At Domestic Surveys we are always experimenting to see how technology can deliver a better survey for our clients.While all the time staying within the price constraints we set for a pre-purchase inspection report. We were the first in the South West  to use the pole camera on every building survey and have been doing so since 2012.

Endoscopes are useful but have physical limitations. We used these for some time as this video from 2013 shows.  This video has had well over 2000 views since being published! We were pushing the boundaries of what we could offer during a full building survey.It’s very difficult trying to hold the endoscope in position for a long period of time whilst using the camera. Definitely not easy with only two hands! Also you need to know where you are in relation to the camera. You have to manoeuvre the flexible neck upwards to look at the underside of the floorboards for example. Lying in the stress position operating this is physically demanding!  Especially after you’veclambered around the loft, hoisted the mast camera, done damp testing, asbestos sampling and tested the glazing.  Certainly a good physical work out!

And now? A robot !

We wanted something small enough to allow us to inspect the undersides of floorboards for wood worm, the size of the floor joists, the damp proofing and ventilation arrangements. We’ve been experimenting with remote control vehicles that are low profile enough to slip into these voids, carrying a camera. We then found this Bluetooth controlled vehicle with profile of around 100mm which can fit between the floor joists in shallow voids. It has tracks so it can rotate on the spot and also it can look up and down.  If it gets lost, it can even find its own way back!

As always, the skill is not in capturing the image but in being able to analyse what the image represents. This may include distinguishing woodworm flight holes from say mouse droppings as they are the same size. Or rot mycelium from timber decay, compared to say cobwebs – another challenge that this technology represents. Getting the images is becoming simpler but analysing the image incorrectly can be a costly mistake.

Take a look

You can see this amazing piece of technology in action here:

We do not do this as standard, YET! We are trying to perfect utilising it but no doubt this will form part of our future offering.  Or on special request if you have a specific floor defect that you wish us to look at…