When buying a house with an extension there are a number of issues to consider.
Local Authority Approvals – buying a house with an extension
The purpose of Building Regulations is to ensure that construction works are carried out to the required standard, are safe and have a satisfactory level of insulation. If you are buying a house with an extension which does not have Building Regulation approval then its construction may be substandard or even dangerous. It is possible that a lack of Building Regulation approval may affect the buildings insurance policy and/or mortgagability (and saleability) of the property.
If you plan to buy a house with an extension then you/your solicitor must make enquiries to establish whether the required Local Authority approvals have been obtained. Obtain copies of all documentation and keep these with your other purchase documents.
However, you may find that the works were carried out without the required Local Authority approvals. If this is the case then the Local Authority may choose to take enforcement action against the owner of the property (even if the works were carried out by a former owner). In other words, if you purchase a house with an extension which does not have the required Local Authority approvals then there is a risk that you will be required to rectify the works at your own expense. The owner of the property may apply for retrospective approval, however, this may delay the sale of the property. A speedier solution may be to take out an indemnity policy. Your solicitor can advise on the suitability of an indemnity policy for your particular situation and can advise on the policy details and any limitations.
For further information on what works require Planning Permission, Building Control Approval and Listed Building Consent visit the Planning Portal using the link below:
Half brick rear additions
Many older properties have additions (often at the rear) which are of half brick (single skin) construction. Some were former outbuildings which have been incorporated into the living space. This form of construction is substandard, may allow rain penetration, high heat loss and condensation. If you are seeking a mortgage then it is possible that a retention may be made (or an undertaking to upgrade the walls) until works have been carried out to a satisfactory standard.
Lack of a cavity tray where conservatories and single storey extensions are provided
Where a single storey part is provided there is normally a cavity tray in the cavity wall immediately above the lower roof. With cavity walls it is normal for rainwater to pass through the external leaf and into the cavity. A cavity tray is needed in this position to help water entering the cavity to pass to the outside instead of causing the inner face of the wall below to become damp. In other words, if a cavity tray is not inserted into the cavity wall where a single storey extension or conservatory are added then there is a risk of dampness to the wall internally, ie, inside the house.
Damp patches may be noted to the wall or wall plaster in the area close to the new abutment to the outside wall. If you are having a survey then your surveyor can check this area with a moisture meter. A moisture meter can detect dampness which may not be visible to the naked eye. If you are having only a mortgage valuation but no survey then the valuer may not check this area with a moisture meter. See also – is a mortgage valuation the same as a survey?
If dampness is noted due to a lack of a cavity tray then it will be necessary to insert a cavity tray at this position.
Low pitched roofs to single storey extensions
Many people would prefer to have a pitched rood rather than a flat roof over an extension as they consider it will have a have a longer life and need less maintenance. Also, many pitched roofs have a better appearance than flat roofs. But many home owners do not consider the pitch of the roof and the type of tile. In many cases the pitch is determined by the size of the extension and the position of any upper windows. In some cases there may only be sufficient height for a relatively low pitched roof.
Each type of tile has a minimum pitch for it to be watertight, ie, roofs below the minimum pitch for the type of tile may not be watertight. For instance, Redland 50 Double Roman tiles should be used at minimum pitches of 17.5, 22.5 or 30 degrees depending on whether the tiles are through coloured or have a granular finish, and also depending on headlap. Therefore, if a pitched roof has a low pitch it is possible that it may not be watertight unless a suitable type of tile has been used such as Forticrete Centurion which can be used for pitches as low as 10 or 12.5 degrees depending on headlap, lap of underlay, etc.
The list above is for general advice and is not exhaustive as further issues may require investigation and enquiries, depending on the property you propose to buy.