Considerations for Small extension without planning permission -

[eileenfrance]

If you are buying a house that has a small extension, without planning permission and one of it's walls is only 8inches from a detached garage, what would you need to think about?

[woofgang]

are you saying that it din't need planning permission or it wasn't applied for?

[eileenfrance]

I don't think it needed planning permission as it's small, however in addition to this I don't think it has any building regulations, so not sure about foundations or lintels. The house is a empty now so there is noone to ask.

[buildersmate]

There's no regulation that says there has to be a gap of minimum size, if that was part of your question.
The issue with small gaps is that rodents, birds and the wind gets in there, and drop stuff (including leaves) which can't easily be got out again.
If you are asking about Planning Consent, you cannot assume that just because it is small, it didn't need planning consent. If it has been there more than 4 years, the planning authority cannot now force its removal.
If you are asking about Building Regulations approval, every extension that is habitable (i.e. not a porch, not a conversatory, connected to the main house via a normal internal door) should have had BR approval. It is the indicator that tells you that it has (probably) been constructed to reasonable minimum standards. Without it you have no idea.
There isn't much you can do about it if doesn't have it - except employ a surveyor to assess the main visible parts. He/she won't be able to tell if the foundations are deep enough though.