Loft conversion together with neighbour?

[Findlebarr]

I have a big decision to make and I’m hoping the collective wisdom of this board will help me!

I bought my semi detached house three years ago. I always had vague plans to do a loft conversion ‘someday’ so that we can stay here for years to come. (DC can stop sharing bedroom etc…)

I have been saving and looking into financing for a loft conversion but with no solid plans.

My neighbour who owns the other half of the semi has approached me to say they want to do a loft conversion and would I be up for doing both at once. I have chatted to them over the years and probably mentioned my vague plans.

I want to consider this seriously. I think there may be benefits to doing the work all at once. But I’m worried there will be penalties too.

Has anyone done this? Is it a good idea? Are there red flags I should be looking out for? Is it a way to save some money? If anyone has any knowledge about this situation I’d love to hear it.

Thank you!

As an architect i wouldnt go down this route

I’d share the cost of works to the party wall perhaps.

Id share the cost of scaffolding possibly but if their side gets delayed it could cost you more ( although some scaffolders aren’t that fussed on timings )

Maybe concider their builder or they yours. He can work on one then straight into the other after. Which might be cheaper.
I wouldn’t do it all together though. You will have no idea whether their costs are more than yours. Whether you end up paying for problems on their side that yours doesn't have.

etc
Essentially it’s two different jobs with two clients and two contracts. not one.

Thank you! These are excellent points which I hadn’t considered.

Just giving this a little bump.

My neighbours did this with a double height extension and it went really well! It was somewhat cheaper- not sure by how much- and the inconvenience was joint.