How long do you think this would take to do?

[brassbells]

Our next door neighbour (joined up via other side of semi detached) said a few months ago he wanted to build a porch, side & rear downstairs extension.
Including a shower room for a new downstairs bedroom, doubling the size of kitchen and porch at the front

Then he decided to build a loft conversion building velux windows at the front and dormer at the back for 2 bedrooms and shower/toilet room

Now he is saying he wants to build everything together and wants us to sign a party wall agreement to agree to this

Does anyone know if there is a maximum time limit on this? (If he only builds the loft or downstairs now then next year he builds the rest)

My DH asked him yesterday how long the builders are saying it would take to build, he said 8 weeks!

We have watched grand designs and so it seems extremely quick

Do you guys think it is possible to build this size extension in 8 weeks?

If not, how long would you guesstimate it would take?

Obviously if it is only 2 builders it could take years but if a building company does it then how long would you guess

He has used "cowboys" to do things like massacre the trees at the bottom of the garden but hopefully he will get experienced builders to do this. Obviously we don't have any say in who he employs to work on his house.

We did a similar-ish extension recently - a 4x4 room with 2x3 en-suite and a 2x4 utility room. The builders said it would take 3 months. It took 6 and could have easily taken longer. No way his will take 8 weeks.

I'd be impressed if it takes 8 weeks. It took 4 to do my bathroom and that wasn't an extension, just knocking down and internal wall and building a different one elsewhere, then the normal bathroom fitting work.

It's just taken five months to do a house renovation with no extension!
Eight weeks would barely get anywhere

It depends a lot on the construction techniques used. If you do a timber frame, things can go up surprisingly fast. However, for most techniques you would need to pour concrete foundations and flooring, and that needs a good month to cure before you can do much with it, so 8 weeks sounds very optimistic.

If I was doing it/having it done I'd expect between 6 months and a year to it fully finished. But most of the big disruptive to the neighbours work would be done well before that.

8 weeks is very sporty. Maybe if they have a big team and everything goes to plan it could be done. But I think 8 weeks is very optimistic.

We're having a one story small extension and flat roof replacement. They have been at it for 6 months and it's still not finished. 8 weeks is very unlikely.

Thank you for all of your messages sort of agreeing the same thing that there is no way it will be finished in 8 weeks

Yeah, 8 weeks won’t touch the sides. The ground floor extension will be the most time consuming, it takes time to do foundations, masonry, roofing, glazing, plumbing, electrics etc. The dormer could be quick, but realistically they are looking at several months, not weeks. I say that as someone coming out of a long extension myself. Ours also involved timber frames which are much quicker. We are still six months behind our 9 months schedule…

Unfortunately you can’t object to neighbour’s work on the basis it will last a long time. That’s not just a valid ground for objecting. So just brace yourself for a longer build (I would think 6 months+ given trade shortages). After that hopefully it will be internal works which won’t be noisy or inconvenient for you.

Communicate with your neighbours about how they can make this bearable for you. We plied our neighbours with hampers, wine, dinner and show tickets, spa gift certificates, redid their gardens, etc. This is because we fully recognise the massive inconvenience our build had on them. But we also lifted their property value with our swanky extension…

Also you do need a party wall agreement. PW surveyors can act as impartial parties, so you can have one appointed jointly. We had a joint surveyor with our neighbours, he was very thorough and said we needed to pay one side for the use of the retaining wall (it was around £900). Our neighbour offered to waive this, but we insisted on paying the award as we have a long standing relationship with them, and we didn’t want to take advantage and potentially ruin the friendship.