Roger Bisby flexes his abilities with a self-levelling compound from Bostik.
I chose to put down some Fibreflex in a loft conversion on what turned out to be the hottest day of the year. It was a foolish undertaking and I should have known better.
Last year I made a video for YouTube on applying this very same self-levelling compound and in it I talk about the need to store bags in the cool and to use cold water.
On a day as hot as that I should have put the water in the fridge or used ice cubes to cool it but I did none of these things.
The result was that the screed had gone off almost as soon as I poured it out. I knew something was wrong because the last time I used this product it flowed.
I bravely continued to trowel it down but in the end I had to abandon it and scrape it up before it set hard.
You live and learn, it isn’t a cheap product so the lesson was hard won but on my next go on a much cooler day with cold water from the fridge it went down with time to spare.
Fibreflex is a protein-free latex compound with fine chopped fibres in it. This makes it very flexible but strong. As far as I am aware it is unusual because the manufacturers say it can be laid on firm floorboards.
It is important that they are well fixed down which often means screws not nails. You need to caulk the gaps first with acrylic sealer and prime the boards to reduce suction but once you have done that you are good to go.
The advantage over using 6mm plywood is that ply tends to follow the undulations of the floorboards so you end up having to lay self-leveller over the ply and I have known occasions where the plywood has de-laminated when I have put the screed over it and that makes a bad surface for tiling onto.
The floor-covering for this job is Karndean, and as many people know Karndean needs a perfectly flat sub-floor to stop the pattern telegraphing through.
With a quick rub over the next day with a carborundum I got rid of any ridges and snots and was ready to go.
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