Frequently Asked Questions

A standard extension from Plus Rooms usually takes between 8 and 10 weeks for the initial build, with a further 6 to 8 weeks to install all required facilities and add those important finishing touches.

While it is certainly possible to extend an existing extension, it can be a complex process depending on the age, size and design of the current extension. More often than not, it is simpler and more cost-effective to simply demolish the old extension and start from scratch.

Generally speaking, a kitchen extension will add value to your property. This recent article from Uswitch estimates that an extension in the London area will add up to £3k per m2. However, we strongly recommend that you speak to an estate agent in your area before estimating the added value of your extension.

Many variables can affect how much value an extension adds to your home, such as the size and age of the extension, not to mention the location of your property. Again, we advise you to consult with an experienced local estate agent before assigning a monetary value to your extension.

You have a legal right to build up to the boundary line of your property, subject to planning permission and complying with all requirements of the Party Wall Act 1996.

Permitted development guidelines for extension size can vary based on the type of property you are extending. As a general estimate, the maximum extension size is 3m for terraced and semi-detached houses and 4m for detached properties.

If you do not obtain planning permission, the maximum extension size is 6m for terraced and semi-detached properties and 8m for detached properties. This would need to be approved under Prior Approval, which is an extension of Permitted Development rights. You can learn more about this by visiting our planning services page.

You need planning permission for an extension when the size or design of the extension exceeds the provisions of Permitted Development or Prior Approval. However, if you live in a flat or your property is located in a conservation area (an area with significant historical or architectural interest), you will usually have to apply for planning permission regardless of the size or design of the extension.

Once you’ve submitted your application to your local authority, the process usually takes 8 weeks. However, you should also allow between 6 and 8 weeks to prepare and submit plans. Overall, we advise instructing your architect or construction company at least 4 months before your ideal start date.

Under permitted development you can extend a semi-detached property by up to 3m, this increases to 6m under Prior Approval. However, you could potentially extend your house further subject to local authority approval.