Replacing rotten floor or wall timbers:
Sometimes when you open up the floor or the wall in a bathroom or a toilet you may come across rotten timber. Simply grab a screwdriver and see what is solid and what is no longer solid timber. Mark out the damaged areas with crosses or a spray can. Then take accurate measurements of the sizing of the timber to be replaced. Get some damp course in a 4-inch (100 mm) roll to assist in packing out the new timber if it is a slightly smaller sizing.
Cut the old timber portion out and replace from the ground up if necessary. You may need a sabre saw, a circular saw or a chainsaw to achieve this cutting. Take a photograph where possible before you cut the old rotten timber out of the way.
Then simply replace like with like. If you have to replace a pile or place a new pile dig this down to solid clay. And place a part of a brick under the pile on top of the clay. Pour in a bag of dry rapid drying concrete. And pour in a whole bucket of cold water. And mix a little to pack in around the bottom near the part brick. Leave to set before putting any weight on this area.
Replacing timbers in the wall area is just the same only you don’t have to concern yourself with the house piles. There are also products you can paint on as timber preservation treatments to finish the job properly.