How do I securely attach a siding frame to a wall made of aerated concrete blocks?
Started screwing the frame under the siding and the problem is that the aerated concrete began to crumble and break off in pieces.
What to do? Maybe I chose the wrong method of attachment?
Aerated concrete blocks are quite brittle material, so conventional hardware is not always suitable for it.
Fastening the frame under the siding is no exception and also causes problems with the reliability of attachment to aerated concrete.
There are a number of special fasteners. Of the nuances – it is important to know
The density of aerated concrete blocks. It is denoted by the English letter D. The numbers after the letter indicate the strength of the material. The higher the strength, the less pores in the aircrete. This figure is needed when selecting fasteners, it is specified in the instructions to the fastener itself and determines the maximum force at tearing out.
Carrying capacity. This figure can be found on the packaging of the fastener. This figure depends directly on the parameters of the fastener (diameter, length) – the larger the fastener, the more reliable it is.
Resistance to corrosion. For you, this parameter is very important, since the fixing will be made outside the building. The metal part should have an anti-corrosion protective layer.
We determined that the metal should have a good carrying capacity to withstand the weight of the frame with siding and resist wind loads, and should be corrosion-resistant.
The more often the fastener is installed, the greater the reliability of the frame. Accordingly, the higher the carrying capacity of the metal, the less often it can be installed.
Here are some options for fasteners:
The most reliable and durable, it is, of course, a chemical anchor.
When assembled, it is a threaded rod embedded in the hole with synthetic resin.
Before installing the stud, be sure to blow the dust out of the hole, fill the cavity with adhesive, and insert the anchor rod. Anchoring with such an anchor will have the highest load-bearing capacity.
Nylon dowel is specifically designed for aerated concrete. It is fixed with ordinary anti-corrosion self-tapping screws.
Steel galvanized dowel. Quite often used for aerated concrete and other cellular concrete.
Turbo dowel. It is made of nylon or galvanized steel. It cuts a thread when screwed in, securely clamped in the cellular material.
And finally. There is a very important rule when installing fasteners in aerated concrete walls – holes under the anchor should be made only with a hammerless tool, it is forbidden to use a hammer!