Fixing internal door linings on aerated block walls

[akist]

I am not sure how to fix door linings onto the blockwork. It is aerated blocks and you cannot really use large screws, the blocks crack. I can get away with 6mm wall plugs drilled right in the centre and a small 5mm x 60-80mm timber screw, but just as a temporary fixing, I would not have a door slamming closed on that. Plus, a screw in the middle of the wall does nothing to hold the lining from twisting.

I am thinking I must use adhesive all around the door lining to secure it in place. Could anyone please suggest the right materials to use, or method?

 

[JohnD]

Clean the walls, remove dust, spray with water to dampen.

Drill holes in the walls for screws and plasplugs loose enough that they will not cause cracks. Clean out the dust. Inject builders adhesive into the hole (starting with the nozzle at the back so there is no air bubble) and press in the plasplugs. Leave overnight to set. I would put one near each hinge position and one on each side of the lock or latch keep as a minimum.

Tap in wooden wedges to hold it upright and straight

Drive in the screws

Inject expanding foam (I use the pink fire grade) into the gap between wall and lining, all round, head and sides. Let it expand go fill the gap and bulge out slightly. The water spray will help it stick and set. The next day knife off any excess.

Use clingfilm to prevent excess or drips sticking to the floor or exposed surfaces.

The foam will hold it firm and prevent it rattling loose. The adhesive will prevent the screws shaking.

 

[akist]

What is the name / make of the adhesive I should be using to secure bolts or plus into aerated concrete blocks?

For fixing the door linings:
1. I cannot use two screws side by side, as is the custom, I can only drill into the centre of the block to avoid cracking
2. The expanding foam will not stop the lining from twisting with time, or shaken off if someone slams a door shut.

For that I am thinking of using restraint straps as in the photo, on both sides of the walls where the door opening is. The straps will be secured onto the blocks with many more screws and then the hardwall over.

 

[JohnD]

2. The expanding foam will not stop the lining from twisting with time, or shaken off if someone slams a door shut.

Yes it will.

 

[robinbanks]

How heavy are your doors!?

I can only drill into the centre of the block to avoid cracking

Who says?