Sounds to me like he intended to use the inadequate polystyrene on its own all a long and only offered to fill the remaining void with vermiculite as an afterthought to keep the client happy/in the dark.
25mm polystyrene as insulation
- Thread starter meb97me
- Start date
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I could be wrong about this but I'm sure poly beads have to be bonded. i.e. injected. Vermiculite, being more irregular in shape, can be loose filled as the work proceeds. So I'd reckon poly beads would be more expensive - particularly for such a small area.
I assumed poly would be cheaper, I only base this on a google search and the cost of a small bag of vermiculite looking pricey?
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The beads are bonded as they are injected and are by their nature non compressible. Vermiculite on the other hand is compressible (ever tried pressing it between your fingers), it is better for loose fill in roof spaces or mixed with cement to make lightweight concrete to fill around flues etc, but not as a cavity fill.
The risk of filling the cavity as you go is when the mortar droppings fill across the cavity and create a cold bridge or even a wet bridge.
The 25mm board should under no circumstances be left in as it will result in an uneven fill and in some areas no improvement on the 25mm of the board itself. There are no benefits to be gained from it at all so get it out.
The risk of filling the cavity as you go is when the mortar droppings fill across the cavity and create a cold bridge or even a wet bridge.
The 25mm board should under no circumstances be left in as it will result in an uneven fill and in some areas no improvement on the 25mm of the board itself. There are no benefits to be gained from it at all so get it out.
I was thinking that. If the cavity is that small, then there's no way loose fill will work from the top down to the bottom.
Did the builder arrive on a horse wearing a Stetson by any chance ?
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