There is a pretty good chance that the next time you need to have your roof replaced, that you will trust that your roofer knows about the regulations they should follow. However, the repair and replacement of roofs are often undertaken without proper attention being paid to the rules. So, as a homeowner (or a DIYer) it is important you understand what is required and how to meet the building regulations for roofs.
Your new roof will need to be covered by Building Regulations if more than 25% of the roof surface is being replaced or repaired. This makes it “building work”. This means you need to notify your local Building Control office and employ a contractor under the Competent Roofer scheme.
If you are replacing your roof covering, the load may increase at the same time. The structure of your roof will need to be checked to ensure it can accommodate this. This might involve getting a structural engineer on board to advise on building work that will need to be done before you can start. This is fairly common in older homes where the roof has not been replaced for 30 years or more.
Your new roof needs to be designed to prevent the build-up of condensation inside your home. This involves the placement of ventilation and insulation in the right places. Failure to do this can result in mould and poor air quality. The ventilation used must be permanent or as a continuous opening in the eaves.
A replacement roof needs to have insulation to the level of a new build, regardless of what the level was on the previous roof. This is usually a U value of at least 0.16-0.18 W/M2K depending on whether the roof is flat or pitched. The insulation should be added with an air gap to prevent moisture.
In most situations you will not need planning permission to replace your roof, however, there may be some restrictions on the type of covering you can use. This is especially the case in a conservation area or on a listed home. You should check any council restrictions by calling the planning office before you start your work.