When taping plasterboard joins, always cut plasterboard tapes to the length required, do not go around corners. Once base coast has set (but not dry) use an 8 inch joint knife to scrape any excess material from the join. Leaving the base coat to dry out before scraping back makes scraping back very difficult. Never try to over fill a plasterboard recessed join on the first taping coat. It is best to tape plasterboard joins before filling external corners. Keep the tape back from the edge of external angles and check for bubbles in paper tape and repair after 1st coat of paint. Remember to make sure all plasterboard joins to be filled are free from dust and loose plaster. Pre-fill any gaps wider than 5 mm before taping plasterboard joins, and check all nail heads are below the surface of the plasterboard.
REMEMBER : Fibre glass plastering tape should only be used on plasterboard wall joins. There are different types of paper tape for plasterboard ceiling joins, plasterboard butt joints and internal corners. Never use fibreglass tape on plasterboard butt joins or internal corners.
Scrape back excess plasterboard jointing cement between coats and do not try to fully fill plasterboard joins on the 1st coat (ALWAYS use a 3 coat system).
Several critical areas to check for a flat finish :
- The junction of a plasterboard join and an external corner.
- The junction of a plasterboard join and an internal corner.
- The Junction of a recessed plasterboard join and a butt join
- The 3 way intersections of internal corners
To check these area use a plasterers 12 inch joint knife on its edge.
Keep sanding plasterboard joins to a minimum, do not to scuff board when sanding. Store bags of plasterboard stopping plaster off concrete and make sure top coat is not out of date (some products can get mouldy if out of date).