Roofs and Structural Problems

We can provide help and advice with regard to building surveys, structural surveys, independent valuations, property surveys, structural reports, engineers reports, home buyers reports or any other property matters . We can carry out specific defect reports relating to roof problems and advise on practical solutions.

We use lots of sketches and photos in our building surveys

As you can see from our articles on surveying we use lots of sketches and photos which we also use in our survey reports as the feedback we have from our clients is that the sketches and photos help them understand the reports better and ultimately solve the problems and carry out the appropriate negotiations. We, of course, like to meet you at the property during the survey and we are more than happy to talk to you about the reports. Please free phone 0800 298 5424 for a friendly chat with one of our surveyors.

A good building surveyor likes going in a roof

We make the comment that a good building surveyor likes going in a roof because a roof is probably the least altered area of a typical property unless of course it has had a loft conversion (more about these later). When we are talking about a surveyor going in a roof we don't mean standing on a ladder looking through the loft hatch, we mean physically getting in the roof. It always makes us smile when we see surveyors in suits or should we say it doesn't make us smile, it makes us concerned as a surveyor in a suit is very unlikely to go in a roof.

In this case during our roof inspection we noted a split in an additional support given to a hipped roof.

What does a surveyor see in a roof?

The inspection of the inside of the loft not only allows the surveyor to look for structural problems in the roof such as wet rot, dry rot and woodworm and general rain and dampness getting in as well as condensation but also the roof is a good indicator of the quality of the building as a whole.

Accessing the roof is essential to see the thinking of construction techniques in the era the property was built.
	Traditional Tudor property
For example, Tudor timber frame properties of years gone by are a work of art and are integral and part of the whole structure whereas a modern prefabricated roof effectively sits on top of the walls. However in both cases when the roof has problems the whole building can have problems.
	Modern Pre-fabricated roof

In our experience of carrying out structural surveys if there are problems with the roof in the form of movement or letting dampness in then there tends to be problems with the whole building as the roof affects the rest of the building.

Roofs under pressure

Although it is not obvious to the untrained eye, roofs come under pressures from many different places; they have the more obvious pressures of their own weight, this would typically be in a house with a timber frame roof truss but there have been eras when we have used steel trusses and even metal trusses within the roof (please see photos below). In fact it could be argued that post war we built as many houses with steel trusses than we did with timber. Equally a modern house with a timber engineered roof uses minimal timber to save money so if things go wrong they go very wrong.

Non-traditional construction	Post war house with steel trusses

Can you see the problems with this roof?

Some roofs are altered and amended over the years. Traditional alterations tend to consist of timber within houses although more and more we are coming across metal alterations post war. Pre war years it was common to use tie bars and more commonly now we are coming across I beams or steel joists being used within roofs.

Roof structure with I beam	If you look carefully you can see a steel beam or an I beam to be exact

 

Steel beam	Tie bar	Tie bar

 

Have a look at the roof covering. Is it the original roof covering or has it been replaced and if so, is that roof covering heavier or different to the original roof covering?

We have discussed how the roof holds its own self weight, the main one of these is the roof covering, be it tile, slate or thatch. All of these types of roofs then have batons that hold the tile, slate or thatch in place.

Have you considered the difference in the thickness between a slate of a few millimetres and a concrete tile of 20-30mm thick. There is also a considerable weight difference and there is also a difference in how these materials react when rain falls. Does the slate for example shed the rainwater and does the concrete tile absorb water?

 

Slate roof	Heavy concrete tiles

Roof spread

It is a fairly well known phenomenon within the building surveying world where the slates are replaced with a heavier concrete tile if additional strength isn't added to the roof structure then you get what is known as roof spread problems where the roof pushes out the main walls.
	Roof spread - heavy roof pushes walls out
Over the years we have surveyed many properties that have had roof spread, some harder to spot than others. In this particular case for example the damage and deterioration to the walls were hidden by stone cladding.
	Roof spread hidden by the adding of stone cladding

Sarking felt or Underfelt or Protective underlayer changes the dynamics of a roof

Since the War Years we started to add a protective underlayer which has had various names over the years. It started as being building paper which was a bitumen building paper and then moved into various forms of felt and in more recent times has moved onto a plastic protective underlayer that is breathable.
	Protective underlayer
All of these change the way the roof works; not only by adding a second protective layer but also by acting almost sail like and helping the roof catch more wind therefore rather than the wind going through the roof it now acts more sail like.	Example of protective underlayer

Weather pressures

There are also various environmental weather pressures on a roof; the most obvious of these is attack from the prevailing wind and rain into the facing roof pitch. As mentioned above, you need to consider the roof almost like a sail as it catches the wind. You can imagine the problems which can be associated with this if thought isn't given to the design, indeed the wind can lift tiles particularly to the perimeter of roofs, and we are finding this fairly common on modern roofs with manmade slate coverings.

Weather pressures	Wind driven rain

In addition to this, what is not as commonly known is that the turbulence of the wind coming off the top of the roof at the ridge then causes a sucking to the rear roof which can cause damage to the rear roof too.
	Man made slates that were lifting on an undulating roof

Alterations to roofs can cause a lot of problems

We would add to this that poor original workmanship, poor materials and poor alterations that are carried out in the form of either major alterations such as extensions and alterations to the roof to fairly minor alterations such as removing supporting walls underneath the roof can all impact on the roof. Depending on what type and style of roof you have it may or may not be able to cope with these alterations and modifications.

Alterations to roof structure

DIY supports added

When we inspected the roof of a property with movement we could see what we can only class as DIY repairs to support the main roof.
	New timbers added in to support roof in DIY standard directly onto plasterboard

What does a roof look like?

We are just going to look at two types of roofs, a gable roof and a hipped roof as this article focuses on pitched roofs.

We would say the fundamental difference between a gable end roof and hipped roof is that a gable end roof takes support from the gable end walls whereas a hipped roof is self supporting, literally leaning on top of itself. In our experience we have found hipped roofs much more susceptible to problems particularly where alterations and amendments have taken place or where there have been defects in the roof materials or workmanship.

Hipped roof

However we have also looked at flat roofs in other articles

Flat Roofs, Problems, Improvements and Insulation

Leaking Flat Roofs

Flat Roofs, Types of Roof Problems

The Rolls Royce of Roofing - Ashpalt Flat Roofs

A few roofing terms which may help you when dealing with roofers

We would like to start with the term ‘fiddler on the roof'. We feel, just like any other work that is being carried out for you, that you have to be very careful about who carries out the work. Many tradespeople can talk the talk very well but the quality of work is debatable. If roofing work isn't carried out very well it can lead to leaking and damaged roofs so it is important to get it right. Generally work on a roof builders or roofers know won't be checked as not many people are keen on climbing up long ladders or even going up a tower scaffold or similar. The other problem is that often roofing work changes as it is only when you get up at roof level that you can see the real problem. You do need to build trust with your builder and/or roofer. Our remedy for this is either getting expert advice or taking a chance and making lots of cups of tea and getting on well with the roofer / builder which is sufficient for most jobs!

'A' frame roof

Definitions

Common rafters

These are the ones that form the pitch of the roof.

Purlins

These are horizontal timbers that give support to the pitch of the roof.

Struts or props

These are diagonal timbers going from the purlins to a point where there is a support from a structural wall beneath. We often come across problems where a structural wall beneath has been removed.

Ceiling joists

These are the joists at the base of the roof and tie the base of the roof together as well as giving something to fix the ceiling to.

Tie or cross brace

This is a horizontal timber that ties the common rafters together and is typically either at the midpoint of the pitch of the roof or in the top third of the pitch of the roof.

Independent Surveyors

If you truly do want an independent expert opinion from a building surveyor, we are happy to do valuations, building surveys, structural surveys, structural reports, engineers reports, specific defects reports, home buyers reports or any other property matters. Please call us today on 0 800 298 5424 to have a free of charge friendly chat with one of our surveyors.

We would be glad to email you several examples of our tailor made reports such as Structural Surveys and Property Reports. We also find that Specific Defect Reports can be used where there is one problem or issue that needs resolving between the landlord and tenant.

W e feel our surveys are quite unique, as they are written to your level of knowledge. As you can see from this article we use lots of sketches and photos in our reports as the feedback we have from our clients is that the sketches and photos help them understand the reports. The survey will also include an action required section and an estimate of costs in the executive summary. We are more than happy to meet you at the property whilst carrying out the survey to discuss any specific issues you may have or have a general chat about what we have found at the end of the survey.

We trust you found the article of use and if you have any experiences that you believe should be added to this article that would benefit others, or you feel that some of the information that we have put is wrong then please do not pause to contact us (we are only human).

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