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.

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.

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 5^th 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.

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

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.