Taking out a chimney breast – Party Wall Agreements

Quite often what appears to be an easy way to make a room bigger in an older house is to think about removing the chimney breast – at first thought it seems easy, knock it out with a sledgehammer, bag up and remove the rubble, plaster up, decorate and hey presto an extra 12 square ft of living space!

And if you’re in London and the south east where this could easily be £450 / square foot that would equate to about £5,500 worth of extra space created…. Bargain!

But… it isn’t that easy. The chimney breasts are part of the building’s structure and taking them out should be approached in the same way as taking out a load bearing wall. The ground floor chimney breast will have the first floor, attic section and chimney stack itself above it –probably the best part of a ton of masonry – and this will all need properly supporting. They may also be shared with next door.

You could of course ignore it, make sure nobody sits under it, cross your fingers and hope for the best, but when you come to sell, a surveyor will spot this. You will then need to do this work which will be far more expensive, or you will not be able to sell the house.

The remaining sections of chimney and stack will need to be supported and usually this will need a steel beam. In some circumstances a system of gallows brackets may be agreeable to the building inspector but you must check with your local building control office first. Supporting the chimney breast on bits of timber nailed to the joists or a scaffold pole slung between two joists (yes, we’ve seen both when doing a building survey!) doesn’t cut it!  You may need the help of a structural engineer to prepare some calculations for you.

Building Control? Because this work is structural you will need building regulation approval and yes, when we carry out a building survey or Homebuyer report for a purchaser, we do recommend the buyer’s solicitor checks the approval and gets a copy of the completion certificate. You can usually use the building notice procedure to get your consent.

So now you’ve got the structural design, the building regulation approval, the sledgehammer and the rubble sacks, you can crack on…. except you can’t, because if the chimney stack is on a shared or party wall you will need party wall agreement.

If you are doing any work on a party wall – and this is quite major structural work – you must follow the procedures laid out in the Party Wall etc Act. At least two months before you start work you must serve a written notice to your neighbours telling them what you are going to do.

Don’t forget, flats above and below as well as next door (yes, all of them against the wall because the chimney goes all the way up or all the way down!), as well as the freeholder, will need notifying. So if there are two flats, that will be three notices and three agreements to get. If they all use a different surveyor this may well cost quite a bit so you should try and get them to use one surveyor and ideally the same as yours, this is known as an Agreed Surveyor.

The Party Wall Act states clearly what needs to be included in a notice but a sample notice is available here. You could put the same information in a letter. It is essential that you write to your neighbour, a quick conflab over the garden fence will not do! We’ve put some free party wall notice templates on our site too – you’ll need to use a section 3 party structure notice

Do not assume your neighbour will agree. If they do, you must get this in writing and it must be signed by them. If they don’t agree you will need to appoint a surveyor and our Fixed Fee Party Wall Service may be a good way of dealing with this.

Just need some quick advice from a surveyor? Complete this form and add your phone number if you want us to call you.


(Originally published by Steven Way, 15 November 2011)