How Much Does it Cost to Demolish Extensions?

Factors in the Cost to Demolish an Extension

As we've mentioned, there are all sorts of contributing aspects of your demolition project that will feed into the price.

Next, we'll look at some of the considerations which may help you understand the questions a contractor will ask before they can provide a detailed quotation breakdown.

Extension Size

Of course, the larger the extension, the more it will cost to demolish. That is not just in terms of labour hours but in the volume of waste to be disposed of, the complexity of the work, and the number of skips (or size of one skip) with capacity for all materials.

Simple extensions may have one layer of bricks, whereas large extensions that form interior rooms may have fully insulated external walls, which makes the job a little more delicate.

For example, if you have a double or triple-height extension, your contractor may need to price in scaffolding hire, demolition equipment and potentially hire an electrician or plumber to disconnect any utilities cabled through the walls.

Location

If you live in a built-up urban area or a remote location, you may need to pay additional costs for travel time, congestion charges, parking permits or licences to store a skip on the street during your demolition.

It is worth having a contractor visit beforehand if there are any access restrictions, such as a side return extension demolition without the space for heavy equipment or vehicles.

Homeowners in London and the southeast also pay around 10% more in contractor charges due to the higher costs of trading in this part of the UK.

Extension Materials

We've touched on the different types of extensions, which will be an element of your budget. PVC conservatories are considerably simpler to dismantle because the frame isn't typically connected to your external walls in a way that will require brickwork repairs or replastering.

If your property was built before the 1990s, it might also contain hazardous materials such as asbestos, which requires special handling, removal and disposal.

Some contractors are specialists in dealing with asbestos, although the associated charges for demolishing an extension with an asbestos roof, panelling or gutters will inevitably be higher.

Reasons to Demolish an Extension

There are countless reasons you might decide that you wish to knock through an extension. Some of the typical examples include:

• Unattractive extensions (often built around the 1970s) constructed from different materials and brickwork than the rest of your property.
• Upgrading an uninsulated, unwired extension into a fully wired extension to use as a larger living space, kitchen or home office.
• Replacing a leaky flat roof with a pitched extension.
• Raising the height of a single-storey extension to a full height extension.

Many older extensions were built purely for functionality, usually as a utility room or spare bathroom, and lack the features we expect from a modern, bright, airy extension to improve the quality and value of our home.

The majority of extensions from around 30 - 50 years ago were also built according to very limited building standards, so they can be structurally unsafe or require replacing as the brickwork and supports begin to deteriorate.

A poorly built extension can cause dampness, draughts, heat loss and water ingress. Knocking through and rebuilding or replacing the extension with a more contemporary structure is often more economical.

Extension Demolition Methods

The method your contractor uses to demolish your extension will depend largely on the nature of the structure and how high the extension is.

Most extension demolitions involve a manual process, stripping out the internal materials, disconnecting utilities, and then working from the roof downwards to remove one layer at a time.

However, if you have a large extension, your contractor may need to use commercial equipment such as a wrecking ball. If the extension rises to the height of the original house, you will also need to budget for scaffolding.

Some materials can hold value and may be retained to use on your new extension or be sold as salvageable items. Examples include things like bricks, roof tiles and slates.

If you believe that some of the materials in your extension demolition are worth holding onto or selling, you can discuss this with your contractor. They might handle the resale and reduce the final cost accordingly or recommend a local builder's reclamation yard that can arrange to collect unwanted building materials.

Other popular areas to compare the cost of demolishing extensions to are the costs associated with demolishing a garage as an alternative, whether its more cost effective to build over existing property or build from new, and how much it costs to dispose of waste materials after demolition.