Plastering hole over thermalite bricks

[imanc]

Hey folks,

The gas man came and removed 6 (!!!) gas fires from around the house and patched over the holes in the chimney breast or outside wall with thermalite brick.

I'd now like to try my hand at repairing these holes and would like some advice.

I plan to use easifill for the top coat and sand back where necessary.

Should I use bonding plaster or cut out various shapes in plasterboard and fill edges for the base layer?

Do I need to bond the thermalite with PVA?

THe plaster around at least one fire is falling away, so it'd be easy to remove a large rectangular section of plaster and dot and dab a piece of plasterboard.

The walls are fairly rough as is and in need of a re-skim. I was hoping that if I can do this work to decent standard, I could skim the room with easifill. If it turns out that it's much harder than I imagine it to be, I'll call a plasterer, haha

Thanks in advance.

imanc

[Tim Watts]

On Friday 22 March 2013 10:54 imanc wrote in uk.d-i-y:

You should use a type of plaster called "hardwall" for the undercoat. The water suckage of thermalite blocks dries normal bonding before it has tile to set properly, leaving it very powdery. At least that is what I saw when I tried a bit.

I do not believe PVA is necessary.

[Andrew Gabriel]

Regular finish coat plaster is not easy to use as a filler for small areas. Doing a whole wall with it is much easier, but you do need to learn how to do it - it's not intuitive.

Or wet the thermalite blocks first (not too much), and use bonding coat.

You want to paint the existing plaster edges you will be bonding to with dilute PVA, and it will do no harm on the thermalite too. If the plaster around is loose, you can try and pour dilute PVA down the crack behind it to stick it back. If you keep knocking off the loose plaster around the edge, you'll probably find you never stop.

[imanc]

I am going to start off with the hardwall and see where I get with it. A plasterer came round today to quote on replastering the entire house and said it would be bad to tackle the plastering myself, so I'm going to try tackling some non essential areas such as to see if I can make it look half decent.