Rain drops keep fallin' on my head
Dab dry lining is a technique used on many modern builds. Apart from the level base for skimming, this technique also simplifies construction of external angles, linings around doorways and windows, etc. Plus, the plasterboard has superior insulating properties not least because it's only attached in 'dabs' to the wall behind. The only place I wouldn't recommend using it is where wall-hung cupboards need to be supported.
So, over the last few days I have been sticking plasterboard to the walls and adding angled plastering beads to the external corners. These are another major help in getting a good straight edge and a flat wall.
Where the patches were small or cupboards need to be hung, traditional mortar render was applied. I can't confess to being an expert at this. The first few attempts were pretty dreadful, with the stuff falling off the wall as I tried to flatten it out. Better results were eventually achieved by upping the concentration of plasticiser in the mix and applying PVA to the surface first. Just as with skimming, generous application of PVA provides the novice with more working time, which is essential in my case! The electrical conduit was sealed in with Bonding Coat. This is more convenient to mix in small quantities - like filler - and sticks to virtually anything.
At last, the walls are starting to look complete, if not a patchwork of textures and materials. I am hoping that a good coat of PVA will even out suction and setting times when it comes to skimming this mismatch!
Sizing up the walls highlighted a damp issue in one corner, which I attributed to the flat roof above. The roof butts up against a side retaining wall (see diagram) and both the pointing at the top of this wall and the seal against it looked suspect. Bitumen sealant (like a mastic) was applied to the seal, while the top brickwork was re-pointed and the render replaced with a waterproofing additive in the mortar. Fingers crossed that will solve the problem.
The membrane-to-sidewall seal and pointing above the tiles needed attention
