External wall insulation – How to install your plinth insulation
Here, using some simple SketchUp models, we look at how to instal the plinth insulation on your external wall insulation project.
2mm Baumit SilikonTop finish render
Baumit Premium Primer
6mm Baumit StarContact lime contact mortar, incorporating Baumit StarTex mesh
Styrodur XPS insulation, mechanically and adhesively fixed to wall (thickness depends on insulation used above the plinth)
Baumit Star Contact cement based levelling coat
Here’s how to install it.
(Click play to activate the model, click the numbers for the annotations, full screen icon bottom right.)
The first step is to clear the ground away from the plinth area, clean the surface of the wall and fill any surface imperfections so the wall is largely flat. The Styrodur XPS plinth boards are typically installed as 1200 x 300mm strips, with a tapered bottom edge as per the model, and the top of the board should be level with where the DPC protrudes.
The back of the boards should be fully coated with the Baumit StarContact contact mortar and then adhesively fixed to the wall. This prevents moisture from wicking up behind the board so is an important step. Once set (usually overnight), insert 3 fixings evenly down the mid-line of the board to improve the attachment to the wall.
Once the Styrodur plinth insulation is installed and the DPC laid over the top, the Ampacoll Komprimax joint sealing tape should be applied 5-10mm back from the outer edge to seal up against the underside of the start track that is applied next. If there is no DPM, this can be applied directly to Styrodur.
The next step is to install the starter track which can be PVC or Aluminium. This should be finished flush with the door openings and mitred on the corners and pressed down so that it sits firmly on the Ampacoll Kompriax tape. This ensures there is a good seal underneath and prevent moisture and any insects from penetrating.
The next step is to install the wood fibre boards. Start by cutting off the T&G profile from the bottom of the boards so that they are square and insert them into the starter track, tongues pointing upwards. Install the boards as shown in the model so that you have a single vertical butt joint in the corner which is achieved by installing all of the boards on each face of the building before moving on to the next. As you butt the boards on the next face up to these the joint must be well glued with the UdiSPECIAL ADHESIVE to ensure that cracks do not form in this area.
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