Loft extension or going above side extension

[Namechanger355]

Hi all

Buying a 3 bed 1930's semi in SW London suburbs - where the current owners have converted the garage into a study and bathroom.

We've been looking at getting an extra bed in for family to stay - is it normally more expensive to do a loft extension or to do an extension over that ground side conversion? How would we go about checking whether the side extension has sufficient good foundations for the latter?

just trying to figure out options.

thanks

It's horses for courses depending on your set-up. A regular loft these days is in the region of 50k & in a 30s house you'll get a massive space + bathroom. A side over-garage room might end up costing just as much with foundation support/walls & roof. Of the two, I'd choose a hip-to-gable loft for the fabulous interior space. More bang for your buck.

You haven't said how long ago the garage was built. I'd assume a recent one could take weight above but an older one, maybe not. I guess you could contact the council to see what plans they hold on it. Short of that you'd have to dig a test pit to find out.

Also, many councils don't allow building above lofts due to proximity to the neighbour. Have a look at the street & see what other houses have done.

Thanks @BoiledFinger . On our road we've seen that quite a number of the neighbours have built over the side extension to create double fronted semis. Good point - side extension was done in 2011 according to the completion certificate.

I have a loft conversion and it's very hot in summer and cold in winter. It has all the proper insulation, it's just that they're not the most practical spade to heat or cool. So based on that I'd go for the side extension if you can. Also you then don't lose the storage space of the loft.

I would assume building above the garage might be more expensive, but from a resale point of view I'd think it's more favourable than a loft conversion. I much prefer bedrooms on the same level.

I have to be honest, I do love a loft extension.

Aside from just enjoying the views from higher up, I like the idea of a bedroom on another level. It provides a degree of privacy which in your case might be useful if you're having guests to stay. A loft extension could also provide the space for your guests to have their own ensuite bathroom. Would your guests be likely to have any mobility issues with extra stairs?

We are expecting our children to be at home longer than average (neurodiverse) so we're planning a loft extension as it will provide more of a feeling of their "own space" as they get older.

Do you have the space for the stairs to go into the loft - would you lose any rooms as a result?

I started the process of buying a very similar sounding property earlier this year but ultimately didn’t proceed as we needed to add another bedroom and unfortunately neither option (above side extension or loft) worked. Reasons being:-

loft - being a semi we would have needed a party wall agreement & the chimney was also in an awkward position. We would also have needed to add a dormer in order to meet the minimum height requirements. All doable but it was going to cost more than just buying a property that had the extra bedroom already.

Side extension- wouldn’t be possible as next door the other side was a bungalow with a chimney near to the boundary (the extension had been built within about six inches of the neighbouring bungalow) and there are regs around minimum clearance around a chimney flue. We would have been too close unless we didn’t build over the entire extension but that would have resulted in a quite small and long/narrow bedroom.

It might be that none of these factors apply to the house you’re looking at but thought could be helpful.

Would also add that a loft extension isn't necessarily viable in all 30s semis - we had a loft company quote, we'd have needed 2 dormers and to lower the bedroom ceilings upstairs to get decent head height. Our (adjoined) neighbours have done it, it's a decent sized room but wouldn't be big enough for a bedroom and an ensuite due to the position of the stairs, and it's got reduced head height (they didn't lower the ceilings) so doesn't conform with building regs and couldn't be described as a 4th bedroom if they sell.

You can instruct someone to dig an inspection pit to see if the foundations / structure of the garage can be built over.