Building Control

Building Control
Building Control

What do Building Control do?

Estate agents, trades men, surveyors even your neighbours will often mysteriously refer to “building control”. Let’s demystify this crucial aspect of the UK’s construction industry. The next series of blogs we will be lifting the lid on this mystery.

Unlike Planning, Building Control, is not interested in the aesthetics and street scape. Building Control is the nuts and bolts. They are looking to see if the standards set in the building regulations have been met. The building regulations are an alphabetised list that sets out the legal requirements that apply to most new building work, alterations, and extensions to existing buildings. They are cleverly written. They do not list the materials required but more the performance that must be achieved. Hence there are many differing ways to achieve compliance. Hence often subjective decisions must be made.

How is this done?

Plan Checking: Before work begins, Building Control will scrutinize your plans to ensure they comply with the regulations.

Site Inspections: During construction, inspectors will visit the site at various stages to check that the work is being carried out according to the approved plans and the Building Regulations.

Certification: Upon completion, Building Control will issue a completion certificate, confirming that the work meets the required standards. This certificate is crucial for property sales and insurance purposes.

Why is it Important?

Safety: Building Regulations are designed to protect people from hazards such as structural collapse, fire, slips and trips and gas leaks.

Health: Regulations also address issues like ventilation, drainage and damp proofing, ensuring healthy living conditions.

Sustainability: Modern Building Regulations emphasize energy efficiency and sustainable construction practices.

Legal Compliance: Failure to comply with Building Regulations can result in legal action and costly rectification work.

Property Value: A completion certificate adds value to your property and provides peace of mind to potential buyers. It also prevents any last-minute hiccups upon sale.

Or at least that is the theory.

EPDM

ethylene propylene diene monomer rubber EPDM
EPDM Rubber Roof

Flat roofing

Ethylene propylene diene terpolymer or as it is much more commonly and easily known EPDM. Not so much of a mouthful! This type of flat roofing is becoming much more popular. The big benefit with EPDM is that is can be manufactured in one sheet. This means there are no joints. Joints in coverings are weak spots.  So, a point of failure. When a complete sheet is used there is a very limited failure rate. Depending on the manufacturer these can have guarantees ranging from 20 years. In the case of Firestone one of the premium manufacturers. They suggest a staggering 50 year life expectancy. This is well beyond any of the flat roofs discussed so far.

Bristol

EPDM, has been popular in America for a long time. The trades are skilled in its use. It has been used for say the last 20 years or so. We first encountered it in 2006 at a London trade show. With popularity in Bristol increasing all the time. Although installers would disagree. It is not ideal to be used when there are lots of penetrations. Such as Velux’s or lantern lights. This is because the main benefit of one sheet is lost. It is still acceptable, but the extra long life spans will be reduced with joins.

Reactive vs proactive

EPDM is being used a lot for repairs. This is where failing flat roofs are simply covered over with a sheet of EDPM. So you cannot always know the substrate. As these have only been used for say the last 15-20 years. We do not really have a good picture as to its life expectancy in the UK, yet.

With EPDM it tends to be the decking that fails first normally related again to the decking onto which it is laid.

The trades perspective

To cover a single flat roof. EPDM – Ethylene propylene diene terpolymer is cost effective and hardy. It is easy to install, only water based adhesive is required. It does get much more awkward, when used on a complex roof. Cutting large sheets is challenging on small sites. Often resulting in smaller upstands and cuts. These can peel off as we show in the picture.

Flat Roofing

Flat felt roof from above
Felt Roof

Felt Roof

There are various coverings that are frequently used for flat roofing. The oldest and worst performing are bitumen based felts. There are varying grades of type of felt. These became very popular in the 1980s. This was due to the very cheap material cost of rolls of bitumen felts. These tended to have a life expectancy of around 10-15 years. Better synthetic felts are now available. These can have a life expectancy of up to 25 years. This shorter life span is due to the damaging UV rays causing the bitumen felts to shrink. They then crack and the upper layers are compromised. Water gets into the cracks/ fissures. It freezes casing the cracks to open further.

Bristol

Felt is still commonly used in Bristol. Even in newer work. The more modern materials are often shunned. In favour of these older materials that are easier to install. Or the trades may have more experience with felts. In our experience the decking and supports are often one of the larger issues. Air flow beneath is key to keeping the deck rot free. The design of the flat roof and pitch is very important and this is down to a carpenter. Rather than the roof covering installer.              

Reactive vs proactive

Flat roofs are often not visible, they are out of sight and out of mind. Especially with a loft conversion. Little is often done with them until they fail. As a result of the short life span of flat felt roofing. Insurers often have specific exclusions. These remove cover with a felt roof over 10 years old. This is problematic when a modern synthetic felt roof fails. However, the exclusion still stands.

People often ignore ponding on flat felt roofing. When a roof starts to pond, the timer has started on its demise. The water in pools freezes. It expands and puts stress on the felt around the edge of the pond.

The trades perspective

Felt used to be melted into place. However now there are safer, self-adhesive ones available. These are the cheapest to install a felt roof is the easiest and cheapest method of flat roofing. The built-up layers mean a fault in one layer does not necessarily mean it will fail. Workmanship is still key to a good felt flat roof installation.

Fibreglass

Fibreglass roof
Fibreglass roof

Flat roofing

Fibreglass flat roofing has been popular for say the last 30 years. It is very good with awkward shapes. As the bandages are easily cut to size. They are good for L shapes and lantern lights for example. They also mould well around service penetrations. The epoxy resins will also adhere to most surfaces. The most common issues are Workmanship based. We would suggest a fibreglass roof should have a 25 year insurance backed guarantee. So it should last 25 years. Although we have seen 30-year-old flat roofs still in service. Although certainly showing their age.

Bristol

Contractor prices in Bristol are catching up with London. Hence the contractors will insist on working even when conditions are unsuitable. Laying Epoxy roofs is a skill full job and requires experience to get a good finished product. Ponding is not as damaging as with a felt roof. But these issues tend to stem from the joiner constructing the decking. Fibre glass roofs are sensitive to the quality of the decking material and layout used. Thermal movement will cause cracks. Issues stem from the carpenter setting out the decking. Rather than the installer of the covering. Often cracks form where the joints in the decking are not staggered. The boarding sagging causing ponding.

Reactive vs proactive

A close physical inspection of a fibre glass roof can uncover problems. Well before they become apparent internally. If insufficient resins have been used. You get pin holing very small holes in the covering these take years to cause leaks. But when they do little can be done. If faults are discovered quickly enough. You can recoat the upper surface. If you can see the fibres readily visible. Not enough resin has been used. Again, another top coat can help.

These issues will shorten the life span significantly. But can normally be seen.

The trades perspective

We have a job booked in. Fibre glass is sensitive to when it is installed. the weather is very important. Too hot, the resins will go off to quickly. This results in very fine cracks appearing. The resins also set quicker meaning you must rush to saturate the bandages. This can result in lumps in the finished roof covering. Similar with most flat roof installs.  Really the job should be delayed. But there is a dead line.

Double lapped concrete tile

Double Lapped Roof Tile
Double Lapped Roof Tile

Double lapped concrete tile

The double lapped concrete tile, is commonly seen on roofing along the coast and generally from the 1930’s onward. These have a suggested lifespan of 80-100 years. These do offer a roof with very long lifespans.

There are more common clay double lapped tiles, on single storey bays and these will last up to 70-90 years. As this was such a labour-intensive method of roofing. It was no seen on main roofs in the Victorian era as much.

The double lapped tile is the much smaller rectangular tile, that are completely overlapped. So in essence you have two completely layers of tiling. As opposed to more common half lapped tiles. These are not half lapped and tend to only be lapped by 75mm or 100mm. So really these should be called a 5th lapped tile!

Bristol

The double lapped plain concrete tile roofs are common on the 1930’s era estates. Such as Patchway in South Gloucester. Some of these roofs that are present do not have felt beneath them. This is as the double lapped tiles offered great weather proofing. Without the need for felts. Unlike the much more common half lapped tile. We often see the lack of felt being cited by other surveyors as reason enough to replace the coverings.

Reactive Vs proactive

Lots of these are still performing well. However as with most things on the assumption they are well maintained. If they are not a value argument can then be made for replacing the entire roof covering.

However, when there is no felt present. There is greater ventilation to help dry the timber battens on to which the tiles are hung. These battens can also be seen throughout the roof covering. Hence, they can easily and regularly be inspected.

The trades perspective

These tiles can last a very long time. Repair to individual failed tiles is relatively easy. Timber wedges placed either side of a broken tile. Lifts the surrounding tiles so a damaged one can easily be removed and replaced. When replacing a double lapped roof. We often see them being replaced with half lapped tiles. This is simply due to cost. Double lapped tiles require more battens, more labour. Hence are much more expensive than half lapped roofs so they are falling out of favour.

Concrete roof tiles

Concrete Roof Tiles
Concrete Roof Tiles

Concrete roof tiles

As we have said previously is expected by testing that clay and concrete tiles have similar lifespan. If not slightly longer. As concrete tiles really became popular after the Second World War had only been regularly used for 70+ years. These again have an expected lifespan of 70 years. We have to be aware that here we are only talking about half lapped concrete tiles. With a suitable profile on a roof pitch of over 30°.

Bristol

In a previous blog 5 years ago (https://www.domesticsurveys.co.uk/2018/08/23/how-long-does-a-roof-last/) we had a concrete roof that was 68 years. The issue with this was the age of other components. The felt, the ridge, the verges. Given the age of the tiles. It would not be wise to re-use them hence they were replaced. Would the tiles last another 68 years? They would certainly not last 138 years. So even whilst the tile may not have reached the end of its working life other components very may well be. However, re-using the tiles to gain 168 years simply would not be feasible.

Hence when re-roofing the tiles need to be replaced.

Reactive Vs proactive

We are now seeing concrete roofs being replaced. In a proactive manner from local authorities. Even on fairly standard or suitably pitched roofs. However, due to low pitched roofs. These were very common in the 1970’s these are now showing significant felt failings. These are now requiring replacement after only 50-60 years. A good example of this is the 1970’s Trendle wood Park in Fishponds, where the roof pitches are very low. Many of these require or have been replaced.

The trades perspective.

It can be considered that trades need/want to guarantee their work. This is a real challenge when dealing with older roofs. They will often only guarantee their work. So if failing occur in other parts these would not be covered.

Trades will often suggest re-using concrete tiles. This is due to ease. They do not have to arrange for waste disposal and delivery of new tiles. They do not have to lift new tiles onto the scaffolding. The older ones can be stacked and re-used close to the roof. Making the job easier. To give some idea. There is a specialist machine called a “bumpa” as this job is so labour intensive. This is a conveyor belt to lift the tiles up two stories.

Lifecycle of Clay Roof tiles

Clay Roof Tile

The Building research establishment suggest a clay and concrete tile have a similar lifespan. Manufacturers will normally guarantee the tiles for 30 years with a 60-year life expectancy. As the BRE is the preeminent body with regards to building science and testing. This links to the British Standard as this will also fed into the calculations as they will define permeameters such as porosity with a seepage tests for example.

Bristol

If you look around Bristol there are countless clay roofs that have exceeded this. After the Second World War clay tiles fell out of favour as concrete tiles were more hard wearing and easier to produce. Hence the majority of the clay tiles that you will see are at least 70+ years old. Which is a above the expected lifespan. Even when a roof has been re-felted and the clay tiles reused they are often in poor condition. The surface is normally pitted and they just tend to progressively get worse.

Likely if a re-used clay tile was tested in the same manner as a modern tile they would fail. For one the levels of porosity would be such that the felt beneath would be doing much of the work. The tiles are supposed to be the primary method of keeping water away from the felt and habitable spaces beneath when they become too porous the roof’s integrity relies on the felt. Felt is not designed to be kept damp for prolonged periods especially modern felts.

Reactive vs proactive again

When re-roofing a property most people do not think about the long-term ramifications. It Is likely that the desire to re-roof is not one of arranged proactive maintenance. A leaking roof needs to be done quickly. It is often an unexpected expense and a very significant one . The idea of spending thousand of pounds to supply the new tiles required for a roof is often one that cannot be readily afforded.

The trades perspective

From a roofer’s perspective it is much easier to remove the tiles from the roof and stack them on the scaffold prior to relaying them. The alternative is to arrange a skip to dispose of the old, buy and deliver the new. Then the labour to bring the tiles from the ground up the scaffolding and stack ready for use.

From a roofer’s perspective it is fairly easy to persuade a customer that the old tiles will be acceptable. Just simply change out the odd one when it gets broken. That being said when the occasional tiles that will get broken during the re-roof the match is unlikely to be exact. This is due to differing brands of tile that are ever so slightly differing in their profile. This means that the tiles do not overlap successfully, as the supply of reclaimed tiles is dwindling this is becoming more common.

Life cycle replacement

Life cycle replacement costings

Verge needs replacement
Wet verge

How to use the data

One of the most common phrases we hear during the survey or as a result of a negotiation is that “it has been fine for the last 40 years so why does it need replacement”?

This sort of comment also tends to reflects that little or no maintenance has been carried out during that period. Martin in the office has come up with his own great answer to this. “If you were standing outside in the wind and rain for 70 years you would probably be a little bit worn out as well.”

This is also one of the common responses from insurance companies the item you are claiming for has reached the end of its working lifespan or the damage was caused by a natural breakdown of the materials.

Reactive replacement vs Preventative maintenance

This is when we start to get into very murky waters. When you look at large housing providers such as housing associations, charities or councils they will have maintenance plans. These are solely based on life cycle data. This is why you will often see them replacing roofs for an entire street rather than just the occasional house. They also tend to carry out timed conditions survey so every five years they will send a surveyor to look at a group of properties and see what needs to be done generally. This informs their maintenance plans. This also allows them to finance the required work and arrange their budget for the coming years. This is a preventive maintenance approach. Remove the item as it reaches the end of its working life in a timed fashion for less disruption.

There is certainly an argument often taken by many private landlords that we will replace it when it fails. Sadly, what tends to occur here is that when the item has been failing for a prolonged period It affects another building element. For example, a leaky roof can cause rot to the roof structure well before visual signs are apparent in the habitable accommodation. Then you have the additional cost of repairing the roof structure, replacing insulation, damaged room or rooms. This means that the repair can become a lot more expensive. As the saying goes a stitch in time. This is very true with buildings and as surveyors we see this all the time. We are usually the ones to flag up the defects.

Life Cycles

Life Cycle Window external beading with gap
Window external beading with gap

Life cycle

There are numerous institutes who calculate life cycle data for the various products and elements of the building. The Building Research Establishment is the pre-eminent source for this data. There are further studies funded by other bodies such as the British Plastics federation and insurance companies. Windows are a good example with a basic google search highlighting almost 30 million results for life cycle of plastic windows.

When surveying it is important to consider the life cycle of the materials involved. This can help us give a time estimate for how long an element may last. This will help our clients plan for the future and potentially when they may need to replace the item. As well as help us report on their condition.

An example

This is when it starts to get complicated as for example the window maker Everest suggests an expected lifespan of 20 years. Whereas the Federation of master builders suggests 35 years. Historically the BRE guidance suggests 25 years but a recent study funded by the British Plastics Federation has made them stretch this to almost 35 years.

When calculating the life cycle of a material it is important to remember who is funding this research and why they may be funding this research. Again, using the example of windows the British Plastic Federation have a marked interest in attempting to suggest a longer life span. Their members will sell more products! Also, the materials and workmanship used in the testing of these products is likely to be much higher than that that would be found in the real world. If you live near the coast for example metal components will corrode much faster. There is also maintenance considerations, has the item been well maintained or not.

The best real world data comes from experience. This is why it is important to have an experienced surveyor look at a property. Again, looking at windows for an example we generally do not see windows operating correctly/efficiently after around 25 years. At this point the frames may be externally beaded. A security concern. The glass is not e-coated so does not perform as well thermally. The metal components will likely be suffering considerable wear and corrosion. The seals will likely have failed around the glass and the frames by this date.

When to test

Given the results of our last blog. This casts an interesting phenomenon related to radon which is the effect of when you carry out the test. The laboratory analysis gave a whole house property average and called it “seasonally corrected”. Whilst no doubt there is a complex formula behind this calculation, we wanted to see the differences and when it would be best to test.

Clearly in our previous blogs ventilation of a property seems to be key. Especially relating to subfloor ventilation and the use of positive input ventilation. The lifestyle of the occupant also appears to be important. Would you leave windows and doors open during the test period. If the weather is warm then windows would be open overnight for example.

The seasonable factor will also have a major impact on results. When we tested during the summer. The results were much lower than when we tested in the winter. So if you are commissioning a test, then you may wish to consider this. Our results showed a much larger change than the “seasonally adjusted” figures showed. So if you are purchasing during the summer the readings will naturally be lower than the benchmark 200bq/m3.

Then there are the much more complex factors related to the geology. Radon gas has a half life of 3.8 days and is water soluble. Given that half of UK radiation exposure is due to radon then the groundwater issue we mentioned in our first blog, have a bearing although a limited one. During the winter when the groundwater tables are higher they also have an effect on the levels of radon being released by the ground. The readings will be higher in winter.

Given this it would be sensible to test for a full 12 month. Rather than the usual three month or 6 month tests that are carried out. This is where electronic monitoring becomes a much cheaper and more accurate alternative. As a full 12 month sample of results would clearly give the correct reading rather than attempting to seasonally correct an average from a specific part of the year.