ᐅ Drilling and screwing into aerated concrete

Hello everyone,

I want to attach roof rafters to my shed. The front wall is mostly made of bricks and those gray hollow concrete blocks. It’s an older shed that I now just want to reroof. To get a straight wall edge, I built up with 5cm (2 inches) aerated concrete blocks. On the other side, there is a 24cm (9.5 inches) aerated concrete block.

My question:
I want to fix the roof rafters with metal brackets. Can I simply drill into the aerated concrete and secure the rafters with anchors and screws, or won’t that hold?

Additionally, on the front wall I have the problem that the aerated concrete block is only 5cm (2 inches) thick, and behind that is a hollow concrete block. Neither screws nor anchors will have much grip there. Do you have any ideas?

Thanks!

How about checking with the common anchor manufacturers? They usually provide overviews

With the 24 cm (9.5 inches) aerated concrete, you can generally use anchors and screws as usual. However, I would tend to drill the hole about 0.5 mm (0.02 inches) smaller so that the anchor fits a bit tighter.

On the other hand, you would almost have to use cavity anchors.

There are Duopower anchors from Fischer, which according to the description are suitable for both hollow and solid materials.

I haven’t tested them myself yet...