When building atop existing single-storey, how much damage done?

[smp50]

When building on top of an existing single-storey structure (in this case a flat-roofed rear extension), how much damage is usually done to the rooms under the new work?

For example - are the existing ceilings taken down completely, all the timbers taken out and replaced, or is the new floor simply put in on top of them?

Does this kind of thing depend a lot on what's found once the felt comes up and we see what the roof/ceiling is like?

I'm sure it all depends on a lot of factors, but if someone could give me some ideas that would be great! I'm trying to ascertain how much collateral damage will be done and what re-decorating will be required.

Thanks,

 

[^woody^]

New ceiling. Possible plaster repairs to top of walls, and redecoration. Roof joists are unlikely to be suitable as floor joists.

New lintels if any existing are not suitable.

 

[ree]

Building up a single story structure to make a two story structure (or more) needs far more consideration than the variables you've mentioned.

First port of call is to dig a test pit to determine depth and type of existing foundations, and the ground type ie. soil, sandy or clay?

There are many other variables - why not research on here. See the Similar Threads at the bottom of the page.

 

[smp50]

Building up a single story structure to make a two story structure (or more) needs far more consideration than the variables you've mentioned.

Thanks, yea - I'm definitely aware of that, but my post wasn't meant to encompass the whole project, haha. It was just one specific query. I've found before that writing too many unrelated things in my posts means that my main point gets missed.

 

[chappers]

Probably as Woody says, but a lot could be to do with running the floor height through when you knock through, it might be possible that you don't have to touch what is underneath at all.

 

[noseall]

Also consider whether planning constraints or practicality allows you to build on the same footprint, i.e. will you need a set-back and therefore steels and padstones etc. A set-back then usually means a small roof and wall plate straps etc.
(Above applicable to side extensions etc).

A standard rear extension would incur the damage already highlighted as well as the obvious water damage from rain ingress.