As Chartered Surveyors we have come across many examples of poor quality workmanship when carrying out structural surveys. This article specifically looks at the problems we see in relation to roofing work. Unfortunately when a roofing job is carried out incorrectly or poorly it will ultimately lead to water getting into the structure. Many times water will enter the structure without being visible for quite some time and can cause damage and deterioration below it. This means it is important that you ensure, when you have roofing work carried out, that it is carried out correctly.

Ponding on an Asphalt roof

What do the circles and ovals mean?

The circles and ovals are a system that we used within our structural surveys and building surveys to highlight problem areas so that you are not left wondering what the problem is.

Our sketches

In addition to this if the photographs do not, we believe, explain the problem enough together with our survey report we also add in one of our own sketches such as the example that is shown here.

Valley gutters

No pins are visible indicating the slates have been masticed in place

 

Slates pinned in place

Manmade slates that have been masticed in place.

Close up of where a tile has been masticed in place.

How the slates should be fixed with a tingle

Roof tingle

Let's talk briefly about why manmade slate roofs are used rather than slate. The main reason is that they are far cheaper. Often a roofer will be able to get a second hand value on a real slate, this would mean a quarried slate, and in the example shown above they may well earn as much by removing the old slates and selling them on as they would from doing the job itself. This is great as long as you know about it and are suitably reimbursed. It is not as great if it is done without your knowledge.

Quarried slate roof

First of all we mean your preparation!

 

Quotations are essential.

You need to get quotations for work on a like for like basis. These should be quotations and not estimates as estimates can change in price whereas a quotation tends to be fixed unless it advises otherwise.

Signs that something is not right - plants growing from the gable end

We have dealt with several problems recently where the initial choice of contractors was based solely on price and not on the work they have carried out previously. The people that were about to use the builders were not aware of any of the builders previous work either in the form of visiting previous jobs, talking to the property owners (how long does it take to make a phone call?) or by seeing photos of their previous work.

Signs that the building job is not right – no mortar in the gable end also known as a verge detail

You cannot compare quotations if you are comparing apples with pears. You need to be comparing apples with apples whilst making sure the brand of apple is the same! If you obtain three quotes for a specific job and one of these quotes is half the price of the others then this generally means that the contractor is quoting for a completely different job.

Our rule of thumb for quotations is for every thousand pounds spent you should have one page of detailed quotation i.e. a £5,000 quotation should have at least five pages.

Sign that the building job is going well – a lead verge to stop wind and rain getting in

First of all you need to define large. In our experience this varies from person to person. The best way to decide this is to say that a large job is whatever you consider to be a large job. This may be many hundreds of pounds or it may be several thousands of pounds.

Ideally in a perfect world the quotation should be a very detailed explanation of what work is going to be carried out and to what timescale. Trade Institutes such as the Federation of Master Builders do offer a standard-ish contract but you do need to distinguish between the contract and the quotation. The contract sets out the rules whereas the quotation explains what will be carried out.

Parapet wall has plants growing out of it. Black tar paint tends to indicate there has been a leak

As we have already mentioned we recommend as a general rule of thumb that a quotation should have at least one page per thousand pounds. On a smaller job we would recommend one page of quotations / explanation of what is going to be carried out by whom and when. It may be worth ensuring that you receive approximately one page per five hundred pounds worth of work.

Firstly felt has been used instead of lead. Secondly it does not sit under the slates enough. It should lap under two courses rather than approximately 100mm as can be seen here.

Over the years materials used in flat roofs have improved considerably to the point where we literally have high performance felt that's elastomeric, meaning that it can cope with movement. However this doesn't mean anything if the flat roof is flat and water sits on it as the water will eventually get into the building.

Mono-ply roof with a felt edging! Yes it was snowing when we carried out this roof survey!

We have also seen the trend of using what is known as a mono-ply roofing system. This is a single sheet of roofing. The best example we have of it as it is commonly known is a fish pond lining. This is very widely used in commercial properties on the hidden flat roofs to a McDonald's fast food restaurant for example or a TGI Friday restaurant.

We have come across some terrible examples of workmanship over the years that have allowed water in or ponding. Often this is on insulation that the rainwater soaks into causing long term damage.

Circular repairs carried out on a fish pond roof

Traditional Cold deck roof with no insulation

Warm roof with insulation

Today we were asked to look at a roofing project on a high level property (by high level we mean over three storeys in height) where the roofer/builder did not think for one minute that anyone would ever look at his work. In this case very basic rules were broken. Firstly only one quote was obtained. Secondly the £5,000 quotation was on one page (so not the one page to every thousand pounds) and this literally said that they would repair the roof but did not say exactly what they would be doing or in how long they would be doing it for.

Fish pond roofs can look good on a sunny day

You may be asking how does such a situation arise? You would be surprised at how often we come across people that just automatically trust builders or have often had them recommended and so trust them.

The largest projects we have seen have had quotations carried out on a few pages for costs in excess of a £100,000. The record to date for a one page quotation is £42,000 although it did relate to other work that was being carried out and for drawings of a kitchen completed by a kitchen designer (even though they were then not employed).

Ponding on a felt roof. Although a felt roof is good it still needs to have a fall on it

 

As with any sales person (and remember that's what the builder/roofer is in this case) they are very friendly and keen to please and will say exactly what you want to hear prior to starting work. At the end of the day it is what is actually in the quote that is important.

Flashing has not been fitted properly

The most common argument and disagreements we feel are about the quality of the work. Running a very close second is the argument about what is or what is not included. Some builders can be remarkably accurate with their quotations but remarkably inaccurate with their work.

Flashing detail

This is also a bone of contention as often builders disappear and work seems to be carried out in an illogical manner. This means that sometimes things need to be done several times and can be very frustrating for someone who is watching this happen.

Basics need to be sorted out such as unblocking drains on flat roofs