On a dwarf wall conservatory built with both skins of concrete block does cavity have to be filled with concre
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The brickwork below DPC should be filled with a dry concrete mix upto 150mm below DPC (2 bricks). This might have changed to 3 Bricks but use to be 2.
The cavity of the wall should be insulated with Kingspan boards. Where this cavity meets the house, the house wall should be cut with a diamond saw to continue the cavity to the house. Otherwise damp can tract across the house wall where the dwarf wall meets and into the conservatory.
no it's not necessary i used foam cavity insulation
It doesnt HAVE to but it will increase the heat and sound insulation.
it would be stronger with concrete filled block
My conservatory cavity was filled with concrete from the foundations up to the finished floor level. From there up to the window sill was filled with fibre-glass slabs.
Built 3 months ago. (UK)
Wayne
Surely the cavity is to stop damp ingress from the outside skin. Most buildings seem to use polystyrene sheets to fill cavities, does same job and helps thermal efficiency. There should be wall ties every so often as well and they should be kept clean of spilled concrete, or you will get damp patches. So why fill the gap with concrete? My thoughts as a d.i.y. er.
Cavity walls are constructed so that there is a gap between both layers of brick's/block's. This gap is there to act as a damp-proofing. Obviously the water that forms on the outside of the brick work can travel through the bricks, the gap prevents the damp from getting to the inside bricks. Usually the space between the bricks is filled with some form of insulation to help prevent heat loss.
If I was you I would not fill the gap with concrete as this will cause damp on your inside walls.
Do not fill the cavity with concrete. As in previous answers by doing this you may suffer damp problems as the cavity may fill up with water and rise above your damp proof course. To add strength to the foundations you can fill the cavity up to 225mm below the lowest damp proof course and no more. This measurement is taken from the current building regulations.
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