I'm going to build a few layers of lightweight blocks on top of an old oak wall plate as part of roof reconstruction.
My plan is a thin layer of mortar on the oak, then blocks and mortar.
Portland will be ok, not lime wont it?
And I dont need a layer of DPC do I?
Maybe some nails or screws down through the first layer to fix it to the oak, or between the gaps between the blocks?
george
(if i can get the blocks, Travis Perkins said theres a shortage of light weight blocks, the factory's shut down for a month)