Folks,
Before I start I am NOT a DIY genius, so I will probably say a lot of stupid things......
I am getting my bathroom changed at the minute - it's a bit of a nightmare and so far quite a few things have gone wrong :'(... Anyhow one of the things I now need to know is how to block up two reasonably large holes in an external wall (maybe about 5cm diameter on inside - probably bit bigger on outside) - these used to take waste pipes, which have now moved. I can look through the holes - you see the internal wall, the insulation (fibre type stuff), the external wall and then the outside world.
Basically I want to know what is the best way to block up these holes. On the inside it just needs to be left flat enough to tile over (may be getting a plasterer anyway so he can probably sort the flat bit out)... On the outside the house is made of block and rendered so think that should be easier than a nice brick house.
I have used that expanding foam stuff before, but not sure how that would work here because of the cavity between the two walls..... also if I used this how should I finish it off on the outside of the house?
A sneaky second question on a different topic.........
We will be having the bathroom floor tiled. There are floorboards down, and I was told to lay plywood. The tiler said 1/4 inch plywood would do. A joiner who was looking at the doors (unrelated I know) advised at least 3/8 inch. Unfortunately I hadn't got the plywood before my plumber started putting stuff in and he kindly laid plywood - unfortunately it is only 1/8 inch..... I take it this useless and I would be best taking it up and starting again with something thicker (which then means the waste pipe for the sink will need to be changed).
OK sorry for being so thick but any sensible answers from gurus would be welcomed.
Cheers, Sam