Building Blox: Week 21 – Expansion joints, Plasterboards fitted

What we did:

  • Expansion joints finished
  • Plasterboards fitted

Now that the ‘first fix’ for electrics and plumbing had been done, the plasterboards could be fitted and ‘skimmed’, transforming the harsh, raw looking masonry interiors into more recognisable home interiors. Albeit, still work in progress.

Allowing for movement in the walls

Before the masonry walls could be covered with plasterboards, the team had to finish the expansion/movement joints. These are gaps in the brick and blockwork which are specified by the structural engineer. Back in week 15 I talked about how I had conflicting opinions on this, with the structural engineer saying they are required and pretty much everyone else saying they aren’t…

Externally, we had applied sealant where these gaps are, but internally we still had some work to do tying the 2 layers of blockwork together using specialist remedial wall ties. One of the issues of course is that now there are gaps in the walls, we still need to ensure the restriction/suppression of fire, air and sound – this could be done by then filling them with specialist foam for expansion joints and even more specialist polysulfide sealant.

Ground floor expansion joints with specialist screws, expansion joint foam and sealant

Ground floor expansion joints

‘Dot and dabbing’ plasterboards

Plasterboards are fixed on to the masonry walls using a method called ‘dot and dab’. This is basically the same as using Blu Tack, where the Blu Tack is instead a gypsum based adhesive… You can see some of these ‘dots’ in the pictures below. Cabling can then be run AKA ‘chased’ in the gaps between the ‘dots’, so hidden behind the plasterboards.

Building Regulations on fire safety (under Part B) require that fire can be compartmentalised for a certain amount of time. This is why the ground floor ceiling is covered in a different specification plasterboard which comes in red.

Similarly, areas where there are water outlets may be plasterboarded in another type, often in green, which is damp proof.

Plasterboarding internal walls is a bit easier, simply screwing them into the timber frames.

Plasterboards fitted to internal wall

Plasterboards fitted to internal wall

Whilst doing this of course, care has to be taken not to cover up the electrics and plumbing!

Plasterboard cut for sockets and plumbing

Plasterboard cut for sockets and plumbing

The tricky ceilings

Having an unorthodox vaulted ceiling created a lot of problems when making the roof, as I talked about back in week 11and was always going to create some more issues when finishing. In this case, as the timbers in the roof were at different angles, including the big valley beam, we had to fit a metal frame below these to level everything out. The impact was that we lost up to 30cm of ceiling height, but when we started with almost 4m in the first place, it wasn’t too much of an issue!

Following on from fitting the plasterboards and to get a nice smooth finish, the plasterboards would have to be ‘skimmed’, laying a thin layer of plaster over the boards. More on that next week.

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