Best way to fill hole in plasterboard

wizzywig27

I recently replaced the thermostats in my house and now I have two square holes in the plasterboard. 

Can anyone suggest (and link) the most suitable items to do this? Someone has suggested expanding foam then a block of plasterboard cut to size (about 5”x 3”) then finally pollyfilla to fill the gaps sanded down?

daveyjp

Youtube is the best place to search for any DIY projects.

wizzywig27

daveyjp said:

Youtube is the best place to search for any DIY projects.

Thank you I’ll go take a look 

Mutton_Geoff

Cut a couple of lengths of batten (19mm x 32mm plenty) to fit across and inside the hole extending 30mm or so either side of the hole. Secure that to the existing plasterboard with a couple of plasterboard screws so that it sits straddled alongside the top and bottom or left and right of the hole. Cut a piece of scrap plasterboard to match the hole size (check correct thickness of plasterboard, prob 15mm). Secure it to your battens with a couple more plasterboard screws. Fill and repair the holes, edges with some fine filler. Sand and decorate. 

Jeepers_Creepers

A photo always helps, Wizzy.

Do you have scrap bits of p'board handy? If not, it isn't worth buying any for this. (Any house renovations taking places locally - keep walking by until the skip has p'board in it!)

Essentially, tho', the job involves fixing a batten or board on the inside of the hole, so that it acts as a backing. You can then fill the actual hole with whatever.

As Mutton says, try and get hold of a timber batten, or piece of plywood - pretty much anything 'boardy' - and cut it to the same width as the hole in one dimension, and around 3" longer in t'other. That way you should be able to slip it into the hole in the wall, and pull it back so's it's tight against the back of the hole, with around a 1.5" overlap at each end p make sense?

How to get it in place? Simplest way is to screw a screw part way into the middle of the panel so you can grab it like a handle to pull the board against the back of the hole. You fix it in place either using adhesive (grab-fill) or as Mutton says - a screw through the wall either side of the hole and into the panel behind.

Once that panel is in place, you can fill the hole... If you have a scrap of p'board handy, cut it roughly to size and screw it in there. Trim the sides of this piece at a bevel, and also the sides of the actual hole so that where the two meet is a 'V'. Dampen the exposed plaster edge and start to fill with an easy-sanding filler, ideally one that sets chemically. Ie a powder you mix with water, and it sets before it actually dries out. You can buy a small box (500g or 1kg) of this for next to nothing in a DIY store. Squeeze the stuff right in firmly, but don't fill it up to the top surface - let the first lot set, and then add another layer.

Sand flat to blend in with the wall surface.

If you don't have a scrap of p'board to help fill the gap, then just build up layers of filler, allowing each one to set and virtually dry out before adding more.

shinytop

Just the advice I was looking for too.   
My local Wickes sells broken plasterboard for a couple of quid.  It may be more than you need though.  

mrluke

depends on the walls.

Dot Dab  ? Plasterboard adhesive + plasterboard + Skim

Stud wall ? wooden batten behind screw into the ends through the plasterboard , then attach plasterboard to batten & skim