Repair wall/doorframe

olbas_oil

I am combining bathroom & toilet, which used to have separate doors off the landing. What used to be the doorframe to the bathroom is to be swung round 90degrees to go across the landing, and claim a little bit extra for the enlarged bathroom.

I have taken out the door frame, and between me and the electrician we have badly damaged the end of the wall. The wall was render on top of block. All the render on the end has gone, with some missing on each side. The block is fairly jagged. I have managed to put up a 2x3 vertical cls stud attached to the wall, and this is in exactly the right position to attach the doorframe. (The other side is undamaged wall, and another 2x3 will be almost the perfect width for the doorframe).

I was doing this to help visualize what the end result might look like, but I wonder whether it is now easier to repair the wall end blockwork with the stud in place, acting like a formwork. Would this be mortar, or could I use expanding foam to fill the blockwork, with a plaster undercoat and topcoat?

The three sides of the wall will be :
stairs - plaster (will be skimmed and painted), end (will be entirely covered by doorframe and trim), bathroom (plaster and tiles). I will be cutting back the stairs and bathroom sides to a clean edge, and then I'm not sure whether the final strip would be better as plaster, or plasterboard?

I may just ask a builder, but if I can finish as a DIY project, what is a good approach?

 

stuart45

There're a few different ways to do the job, but probably the easiest for DIY is to fix the 3x2 properly to the wall making sure it's plumb, then fix the door lining. you can then tack a strip of plasterboard to each side, scrim the join and plaster it flush with the existing. You can also use sand/cement render instead of plasterboard, but the 3x2 will need EML. More complex is to build out the jamb to size in masonry and fix the lining to that.

olbas_oil

stuart45 said:

There're a few different ways to do the job, but probably the easiest for DIY is to fix the 3x2 properly to the wall making sure it's plumb, then fix the door lining. you can then tack a strip of plasterboard to each side, scrim the join and plaster it flush with the existing. You can also use sand/cement render instead of plasterboard, but the 3x2 will need EML. More complex is to build out the jamb to size in masonry and fix the lining to that.

Thanks. That sounds like a good plan. But this will leave voids behind the new plasterboard. At worst there might be gaps a bit larger than tennis balls, where chunks of blockwork have fallen out.  Should I be filling these? With what?

stuart45

Although you can have voids behind plasterboard, as in stud walls, I'd probably fill them. You could use mortar and bits of the broken pieces of block. 

DRP

olbas_oil said:

stuart45 said:

Thanks. That sounds like a good plan. But this will leave voids behind the new plasterboard. At worst there might be gaps a bit larger than tennis balls, where chunks of blockwork have fallen out.  Should I be filling these? With what?

fill with tennis balls!

(sorry)

olbas_oil

stuart45 said:

Although you can have voids behind plasterboard, as in stud walls, I'd probably fill them. You could use mortar and bits of the broken pieces of block. 

Is expanding foam a reasonable alternative, or would quickset mortar be best? I've already chucked the bits of block.

FreeBear

Filling the gap with mortar & brick/block gives a solid surface for the frame to rest against. Should you ever need to put an extra screw in to stop the frame moving, there will be something solid in place.

Bodger's Foam (expanding foam) will provide little support. It is OK (sometimes) to use expanding foam to fill a small nonstructural gap  to provide backing for plaster.

stuart45

Main thing is to get a good fix for the 3x2 into the blockwork. Foam would be good for the small gaps. For the bigger gap if you have any old bricks lay them on edge instead of a cut 3 inch block. It doesn't matter too much if you are boarding over. On site it would probably be left and boarded, but when working in people's houses it's better to fill up the gaps to make them feel better about the job.

olbas_oil

OK it's mortar and some old brick pieces. I'd like to use rapid set cement . What ratio cement/sand/water is best for this purpose?

stuart45

6/1 for that job. Water depends on how wet the sand is. Just enough to make it workable.