Ceiling plasterboard lifting in one corner

[frankgoldstar]

Bungalow built in 1959. The man body of the house has a main pitched roof that ends in a valley rafter above the corner of a hallway. The gutter here was not cleaned for some time and was full of debris until cleared two years ago. The internal evidence of damp was also cleaned up.

However, attempting to plaster small cracks on the ceiling/wall join reveals the plasterboard in the corner can be lifted up by around 2mm. 200 - 300mm away the plasterboard is fixed ok.

As there is no evidence of continuing water penetration, or remaining damp, would simple fixing of the corner to the ceiling joists be a reasonable fix?

Access to the loft is difficult, and the area is right at the edge of the ceiling joist/rafters, with limited access under a purlin.

Best, Frank B

 

[frankgoldstar]

Update. Checking the ceiling joists with a magnet, they are not spaced evenly. Checking in the loft (grrr) confirmed this, so another check was made and it was obvious the plasterboard is simply not fixed in the corner to the joists at all.

The board will be fixed as near as possible to the corner and any small cracks filled. Best, Frank B

 

[Deleted member 292770]

if you can get up there. gripfill a timber above the corner .

 

[JohnD]

A method I found successful:

In the loft, clean and vacuum the plasterboard, joist and adjacent wall. Cover any cables. Prop up the ceiling from below if necessary to make it flat and level. Wrap your prop board in clingfilm to permit easy removal.

Spray the plasterboard, joist, wall, from above with clean water, and apply pink fire grade expanding foam, especially into the joints and corners. When it sets it will hold the joints together and the board to the wall.

In ths old days I repaired L&P ceilings with expanded lathing and pouring plaster, but the foam is easier.

 

[frankgoldstar]

Thanks to both Godwasaplasterer (great name) and JohnD for the replies.
The plot thickens a bit, as the ceiling joists get a bit scarce right in the corner.
I looked in the loft as near as I could get easily and measured the centres, but they seem to not get all the way to the corner....
I did a better look see at the actual lift of the board down in the hall, and it is probably less than a millimetre right at the corner. The existing crack in the wall made it look bigger, particularly as this is pretty black from the dirt that has blown through.
I do need to fasten it, as it is opposite the front door and with the wind that always blows down this road (property less than two miles from the coast) the original crack was very probably caused by the plasterboard being lifted as the door is opened. It is a big horizontal sail after all!
I do have problems in getting to the area too, much less removing the blown in insulation under the fibre glass stuff, then cleaning and sorting it out as suggested, so I am inclined to have another think about this.
The good lady of the house is not at all enthusiastic about anyone even accessing the loft as the blown "insulation" then appears to want to invade the rest of the house.
Whoever invented that stuff needs feeding with it.
So a good think about the problem while she cools off is called for.... Best, Frank B