Frequently Asked Questions

A standard extension from HCH 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.

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. We will discuss this with you on our initial site visit.

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.
However, an architect may be keen to draw up plans that keep 1 metre away from the boundary to avoid any possible disputes, so speak to us before confirming any plans to be submitted.

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.

Within Permitted Development Rights, 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. It is important that you discuss any plans with your neighbours as if they do not object, the process will be quicker and cheaper! We will discuss this with you on our site visit.

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.