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.

After the previous blog on our experiment, we thought we could follow this up with the use of an electronic radon detector meter. We read various reviews, the one with the highest reviews was the “Airthings Corentium home radon detector”. However, most of the negative reviews related to the fact the machine wasn’t working on arrival. We paid £108.00 for it on Prime Day but without was £169.00. It visually appears identical to the “Canary” which from PropertECO was £165.00.

Ours arrived on Amazon Prime and worked straight out of the box. It stated the detectors in the meter were the work of the CERN laboratory, which gave us confidence.  It took a few minutes to self-calibrate. We purchased this meter to see if we could get a snapshot during a survey. To see if during the 4-5 hours spent on site would be sufficient enough for us to gain any meaningful reading. This meter takes 24 hours to give the first readings. So, using it in any less of a time frame than 24 hours is not possible. So, no use to a building surveyor doing residential work.

From a homeowner perspective however to be able to get some sort of meaningful results in 24 hours without having to send off for a 10 day laboratory test could be a great advantage for the short term needs of a property purchaser in a high risk Radon area.

Seasonality

The laboratory tests offered a seasonally corrected value. As the electronic meter was used after the laboratory tests. It was exceptionally warm during the second test period. hence doors and windows were open. This does appear to confirm that winter readings will be higher than summer readings by a significant margin. This will be a subject of a different blog.

So the results do show a fairly major difference. We expected them to be proportionally different but that does not appear to be the case.

What do you do about Radon.

Ask if the property has been tested, is a fairly easy one top start. Given that since 2002 radon has been raised as a compulsory question in standard local authority searches. It may well have been tested already.

If it has been tested interpreting the readings may be challenging. The units are measured in Becquerels per cubic meter. In essence the average levels in UK houses is only 20bq/m3. That being said the lower the levels the better. The government has endorsed a recommendation that when 200Bq/m3 is reached then levels need to be reduced. Interestingly under the Health and Safety at Work Act the legal duty on an employer and workplace buildings is set at 400Bq/m3.

It is good practise that even when the property has been tested and remedial measures put in place then the property is retested afterwards. This could be interesting; as new properties say post 1999 or extensions constructed recently may have had the detailing installed but may not be functioning properly for example.

How do I know when to get a property tested?

The NRPB (National Radon Protection Board) suggests that when the risk is low 1-5% chance of the property having an issue, the purchaser may simply risk the small chance that they may have to spend money later reducing the amounts of radon in the building. However, it is suggested where the risk is higher say 10 -30% then the purchaser may want to protect themselves.

If testing has not been carried out you could consider re-negotiating the price to account for any remedial works that may be required. Such as installing the radon barrier and sump with electric fan. Installation of a positive input ventilation system (PIV) system. You could simply accept that the cost of the property is plus the cost of any remedial repair work required.

Legal advisors may be able to offer a service such as a radon bond or a Radon Retention. Where an amount of money is taken back the purchase price until the test results are received. If the levels are acceptable, the money is released back to the vendor. If the readings are excessive then the money is released to the purchaser to pay for remedial work.

What do you do about Radon and the compulsory question?

Since 2002 Radon has been raised as a compulsory question in standard local authority searches. So an easy way to deal with this is to ask if it has been tested.

Interpretation of readings

If so, interpreting the readings may be challenging. The units are measured in Becquerels per cubic meter. In essence the average levels in UK houses is only 20bq/m3. That being said the lower the levels the better. The government has endorsed a recommendation that when 200Bq/m3 is reached. Then levels need to be reduced. Interestingly under the Health and Safety at Work Act the legal duty on an employer/workplace buildings is set at 400Bq/m3.

It is good practise that even when the property has been tested. Then remedial measures put in place then the property is retested. To ensure the levels have been reduced. This could be interesting as properties say post 1999 or extensions constructed recently may have had the detailing installed but may not be functioning properly for example.

The NRPB suggests when the risk is low 1-5% chance of the property having an issue. The purchaser may simply risk the small chance that they may have to spend money later on reducing the amounts of radon in the building. However they suggest where the risk is higher say 10 -30% then the purchaser may want to protect themselves.

What is it has not been tested

If no testing has been carried out you could consider re-negotiating the price to account for any remedial works that may be required. Such as installing the radon barrier and sump with electric fan. Installation of a positive input ventilation system (PIV) system can also be beneficial. You could simply accept that the cost of the property is plus the cost of any remedial repair work required.

Legal advisors may be able to offer a service such as a radon bond or a Radon Retention. This is where an amount of money is taken from the purchase price. It is held back until the test results are received. If the levels are acceptable. The money is released back to the vendor. If the readings are excessive then the money is released to the purchaser to pay for remedial work.