replacing ceiling joists

29 Apr 2012
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United Kingdom

we have our kitchen work started today. there was a suspended ceiling in kitchen (like in office). behind suspended ceiling was the original ceiling.

plan was to remove suspended ceiling and plasterboard over the old original ceiling. today once suspended ceiling was removed, we found the original ceiling above it is sagging , there is a crack where from discolouration it appears there is some water damage and is moving when pressed.

builder will look at it tomorrow but he told me the joists above may be rotten and may need to be replaced.

i know this yet to be confirmed and i dont have any other details. but in general what is involved in replacing rotten ceiling joists (above the kitchen is bathroom). does it mean ripping out tiles in bathroom and may even be adjacent room.

i know i dont have more details but just want to get some idea if i know i can ask right questions to builder. and are there any ways around this?

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you'll want minimum disruption upstairs. It's possible the joist are rotten under the bathroom area if there have been leaks, but more likely - if it's an older house the lath and plaster has all come loose (with water damage?) causing the sagging.

If you want to be sure, take the kitchen ceiling down. It will be messy. It's unlikely you'll be able to only take a small section down easily to inspect if it already sagging in places.

If you're in luck, the joist are fine and the new plasterboard can go on the existing joists.

If the joists are damaged / rotten then I'm sure the builder can sister new joists along side any existing damaged ones from underneath after removing damaged sections. At worst for an old leak, only a couple of joists will be damaged around the area there was a leak in the past
Why not go up to the bathroom and investigate the bathroom flooring - including under the bath, and behind the toilet.
Is the floor level both ways?

Look for sagging, bounce or obvious water damage.

Is the kitchen ceiling plaster board, or plaster lath?
Even with p/lath you can open inspection holes.

Usually, the whole ceiling has to be dropped to make a better job of it.
Although you can p/b over the in place ceiling.

Or, if the difficulty is in one or two places only then cut it out, and piece in p/b, and then PVA and skim the whole ceiling.
It depends on whats up there, and its surface condition, and the kitchen footprint.

If any joists have rotten tails, or are fungal damaged in the span, or if the rot cannot be cleanly cut out leaving some sound timber, then remove the joist, dont sister to it.

Try and do all and any of this work, including misting coat, before any units enter the kitchen.

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