How long does it take to get permission for an extension?

Lisa Raynes

by Lisa Raynes

20/09/2018, in Liverpool Blog | Main Blog

Here is an explanation of our process, along with the expected timescales.

Our process starts with free online consultation, which usually has a waiting list of 2-3 weeks. Then we will book in a design workshop, which we advise should be at least a week from the consultation to give you a chance to get a laser measure to measure the dimensions that we ask for, so we can accurately draw your house for the workshop.

After the workshop we arrange a follow up a month later so you have a chance to speak to builders to get an idea of costs, speak to estate agents to get an idea of value, and speak to neighbours to see if there are any showstoppers. In the follow up we can sketch out a definitive concept design, and hopefully you will have made a decision as to whether you want to go ahead, so we can move forward into Stage 2.

For Stage 2 we come and do a full measured survey, which depending on Alan’s availability, usually takes about a week. Then it may take us 3-4 weeks to draw out the existing and proposed plans on CAD in 2 dimensions. Then your architect will come to your house with the proposals to see the project in real life. Subject to final tweaks, the project will then be ready to submit for planning, permitted development or building regulations.

What permission we get will depend on what needs doing; as a rule, if you’re just doing internal works you will just need building regulations; if you’re making alterations to the front, or extending then you will need planning or a certificate of lawful development.

There are lots of exceptions to permitted development, around heights, levels, looking down existing structures, etc, which we will be able to gauge once we have drawn out the full scheme. If you go down the planning route, from validation it is 2 months before determination, although planners don’t look at it until the determination date, and then they may ask for an extension of time.

Alternatively, we could go down the permitted development route; it takes 6 weeks to get a certificate of lawful development, however, we might get knocked back considerably, forcing us to go down the planning route.


Once you’ve got either planning or a certificate of lawful development, the next stage is building regulations. At this stage we will do a detailed set of drawings, coordinate with a structural engineer, a building inspector, and a party wall surveyor, which may take a month or so.

Once we have got the structural and the detailed building regulations drawings, we use private building inspectors, rather than going through the council, as they get building regulations approval relatively quickly.