Historic buildings often had open roof structures with no party walls in the loft spaces nor above the roof lines. If a fire did happen in a property on a terrace. It spread through properties very quickly. As a result, party walls in the loft space became more normal and the raised parapet became common normally topped with a coping stone. These raised parapet walls between houses are some of the character features we expect to see in Victorian era housing.

Why is it important

Where you put an exposed wall above the roof line. Dampness is not far behind. They form a natural weak spot between houses for water penetration. Originally, they would have been cast or cut stones fixed to the top of the wall with mortar. They were intended to help keep water out of these exposed walls.

The lower parts of the wall had to be rendered to try and keep the water out. These rendered sections were very hard to see from ground level and often failed as they were out of sight out of mind. Until the ceiling became damp. Then lead flashings and soakers had to be used to join the roof and the raised wall together.

This is a very complex way to create a roof structure. As it is complex any one of these components fail then water can penetrate into the loft and work its way into the room beneath. One of the most common failures are poor overlap of the coping stone over the wall. The NHBC give guidance for modern buildings suggesting a minimum overhang of 40mm. This is not often achieved. Especially if walls have been re-rendered.

Are they stone?

Older and higher quality buildings actually used stones. Normally limestone. If stone were subject to heavy weathering. This often-caused them to delaminate and spall. The thinner the stone the more likely water could penetrate through its thickness. As an example, is shown in the picture.

Then came the cast manufactured stone, these were mainly concrete. These weathered better and were often triangular shaped to help shed water away from the wall. However, where the copings meet each other there was a slight gap for the mortar. So the quality of the coping was reduced by this mortar band.

How do you solve this?

Replacing the coping stones and detailing with a modern plastic damp proof course beneath is a an expensive but longer term fix for the issue. The damp proof course needs to be “fully bedded”. This means that the plastic damp proof course needs to be laid on a thin bed of mortar then the stone fixed on top with another layer of mortar. Effectively sandwiching the plastic. If not slight settlement/shrinkage will cause the damp proof course to lift off the wall. As can be seen in the picture below.

We often see now, that older coping stones on raised parapet walls, are covered over with leadwork. Although expensive this is a good way to deal with penetration through the stones. Again other modern materials have been used such as felt and fibreglass to water proof the top of the stone, these can be acceptable but have a more limited life.

A picture says 1000 words.

As part of our desktop research, we always look at the agent’s pictures and floor plans before arrival. This gives us a good idea of what the property condition is like and what we need to look for. With returning clients who have sat through one of our feedbacks and understand the terminology. We will look at these pictures prior to them making an offer to give some feedback on potential issues. This is so that a property with significant issues, such as missing chimney breast or severe structural movement can be avoided.

There is no charge for this, as we want our clients to get the property that is right for them. As our reviews also show this. “Even before they conducted the survey they checked the history of the property, issues and concerns – this helped me decide, before paying any money out, that a property was unsatisfactory. This led to finding the (almost) perfect house.”

What we didn’t know.

We are friends with an agent in London and they mentioned during a conversation that they edit their pictures. This produced a long conversation as to how ethical this was. They said it was to touch up on various imperfections normally due to issues with taking pictures. Such as light and shade. They did say there was a service offered to make a property look lived in. They will add furniture and appliances to the pictures for a fee. This surprised us we had noted the increased use of fish eye lenses and such to give the impression rooms are larger than they are for example.

Is it ethical to alter pictures?

On our Facebook profile we were sent an advert by “Made Snappy”. Probably as our profile says we are in real estate. The advert states that well known estate agents such as Town and Country, Hunters and Martin & Co. use their services to touch up their pictures. Again, we did not consider this until we saw that one of the services offered was VC which we presume is vertical correction.

One of things that is most obvious in our initial looks at a building is leaning, where there is clear guidance under the BRE 251 digest. Until we saw the promotional picture used below. This begs the question how far is it ethical to touch up pictures, to hide movement? To airbrush cracks or damp spots? We will leave that for our clients to decide, but it could certainly cause stakeholders time involved in the purchase to be wasted. Should the pictures be marked to show they have been altered?

New Build Snagging

We made a decision in 2017 that we would not longer offer to carry out snagging surveys. The last one we carried out took weeks of back and forth to arrange. Then a challenging full day of inspection. Followed by one day writing the report and referencing the NHBC guidance at each stage. Then another day creating a useable spreadsheet for the developer. The fees we charged for this were fairly minimal and meant there was no business case for continuing to offer this work.

The market

There were lots of firms offering snagging services at the time but the quality of these differed significantly. From basic “counting the screws in the hinges” to better quality. There were no trade associations linked to the quality nor benchmarking. So, there was no set standard. Hence ours which was far more in depth and referenced the standards, was massive compared to the volume snagging reporting firms. The prices were incredibly low, we did not know how a good job could be done for the money. Invariable a good job was not done. We see this when doing homebuyers reports of more recent housing and defects that have not been spotted now. With vendors dealing with the fall out

What changed

We were asked to visit a new build property for a returning client that we had done two older houses for previously and genuinely liked them. We only allowed an hour or two on site. So said we would have a nose round with them. What was found was shocking. Truly shocking. Uneven floors, walls out of true, poor detailing, cracking generally. The site agent assured us that these would be dealt with. The only way to sort the floor was to remove the Kitchen, a very costly and damaging exercise. This was all spotted with 2 hours. Here is a slide show of just a few of some of the issues we have found.

We felt the need for a better-quality professional service was required. There are other companies coming to this realisation. With well-known you tube channels showing the poor workmanship and corner cutting that appears rife, this has actually become comedy viewing.

What is the future for snagging surveys?

We teamed up with Gary. He is an ex-site manager with 30 years’ experience in Construction. Thus he became the perfect Poacher turned Gamekeeper. He has previously worked for the NHBC and is site manager trained. We have created our own bespoke document to able quick and easy delivery of the information in one annotated picture-based report. The RPSA must have been having the same thoughts as us. With this market dominated by volume house builders marking their own work. They have just introduced their own new reporting standard. Gary Has attended the recent training for this as well and can offer the RPSA version or our own bespoke

Breathable felts

The history of breathable felts.

Breathable felts were first thought about in the 1980’s. They started in Germany as a result of changes in their building standards. The first patents were made in 1983. However, such felts were not widespread in re-roofing in the UK until around late 1990’s. They began replacing the plastic grey Monarfoil felts which caused significant condensation in roof voids (Sarking felt or underfelting through time – Part 3). So, if you see a white, blue or green felt in the loft you know it is a modern felt and less than 25 years old. It may not necessarily be a breathable felt, but it can help to give an indication of the age the roof.

Although breathable felts are the optimal product to use today, some modern felts are not breathable. These rely solely on lots of other ventilation details being present. This will help the roof to breathe and reduce the effects of condensation in the timber components of the roof.

What are breathable felts?

Breathable felts are very clever when correctly laid. They are very strong made from non-woven polypropylene. They are resistant to UV degradation. Although if left exposed to the elements will eventually shred or rip. This is why eaves carriers became best practice. Changes to the British Standard 5534 in February 2015 included these plastic trays that hold the bottom of the felt up where it meets the gutter.

The problems with modern felts.

The makers are very specific about what other details are needed. Although these differ between manufacturers. These may include ventilated ridges, or hips. Where an air gap is left at the top of the roof to allow for better air flow. Vented soffits where the soffits have grills to increase air flow. These are often omitted in the mistaken belief that breathable felt on its own is sufficient. We have made a YouTube video of what happens if these details are omitted. https://youtu.be/GNsB8qc-_ns

The risk of overstretching felts is another challenge for roofers. The felt should drape over the rafters and have some sag. Clearly a roofer doesn’t measure the sag on each piece of felt. It would take forever to install a roof, but 10-15 mm is generally acceptable. Remember that the purpose of roofing felt is to divert back into the gutters any rain that is driven beneath the tiles by the wind. The correct sag allows that wind-driven rain beneath the tiles to run down the felt without touching the wooden battens and causing them to rot. You should be able to get your hand between the felt laps; if you can’t, it is too tight. There are visual signs of this defect; mould growth to newer felts is a symptom of over-stretching. Once stretched this will shorten the lifespan of the roofing battens and the roof will require re-felting again.