Sheet Materials

Not all boards are the same. Put standard plasterboard in a wet area and it will swell and fail. Put fire-rated board where it is not needed and you have spent money for nothing. Knowing which sheet material goes where is one of the simpler bits of knowledge that saves real problems later.

These guides cover the sheet materials and joint tape used to line an extension: standard plasterboard for dry walls and ceilings, moisture-resistant board for areas that get splashed, fire-rated board where Part B asks for fire resistance, and cement board behind tiles in properly wet areas. Each page explains what the product is, where it is required, and what to look for when it arrives on site.

Where to start

Start with standard plasterboard, because it lines most of your walls and ceilings. Then read moisture-resistant plasterboard, which sets out the decision between green board and cement board for each zone of a kitchen. If your extension has exposed steels to box in, fire-rated plasterboard matters too: fire resistance comes from the whole system of board, screws and joint treatment, so a pink board fixed like a standard one may not pass.

The guides, grouped by job

Boards. Standard plasterboard, moisture-resistant plasterboard, fire-rated plasterboard and cement board for tile backing.

Joints. Scrim tape, including when mesh tape suits the job, when paper tape is the right call, and why internal corners are where cracks tend to appear.

Where these fit in the build

Fire-rated board is used to box in beams at steels and lintels. The rest go up at plastering, with moisture-resistant and cement board carrying on into tiling. To check how many boards you should be paying for, use the plasterboard quantity calculator.