One of the common mistakes I see people make is connecting their existing outbuildings to their home, converting outbuildings into accommodation or renovating older extensions or using conservatories or orangeries to create bigger brighter family spaces, without first addressing the issue of insulation!
Older extensions, outbuildings and conservatories have often not been designed as year-round accommodation, and are therefore not suitable for use as such, without a fair amount of preparation.
There is absolutely no point in shelling out a load of money on a lovely bright new kitchen, flooring, bi-folds and Velux windows, only to find you freeze in the winter or have problems with damp, because you simply don’t have sufficient (or any!) insulation. This means it’s absolutely crucial to make sure the roof, walls, floors and damp-proofing can be brought up to scratch before you do anything else.
Firstly, make sure you have the building - whether attached or separate to your house - surveyed or looked at by an expert who can give you advice on the current structure of the floors and walls.
Then, get advice on the best way to make those existing structures fit for purpose. This may mean ripping them down and starting again or you may be able to create layers by building walls inside the existing walls and raising the floors to allow for the necessary insulation. NB. This makes your interior space smaller.
All this can be done but you will need to be realistic with your budget and make sure you get someone in the know to help you with adjustments for things like window height, staircases and any other structures that may be affected by changing floor levels.
Sometimes, it’s simply easier (and cheaper) to demolish and build from scratch, but either way, being prepared and making sure you have addressed all the insulation issues for your extension or annexe will save you money in the long term.