France in Focus

Does anyone have any advice on techniques for cutting and installing mineral wool insulation, please?

You can cut it with scissors or if very thick with garden shears. You will blunt them though. Sharp bladed hobby/DIY knives (Stanley knife for example) will also cut it but it is much more laborious and you will likely need several passes.

Wear disposable overalls tucked into socks and hood up, gloves, a dust mask and goggles. You want to minimise contact with the fine fibres with your body - inside and out. It can be extremely irritant.

If you do end up with itchy skin, you could try Uriage eau thermal Xemose which does sooth the skin and help stop itching. Available from the pharmacy.

That stuff is savage. If I could survive contact with it my place would have been insulated ten years ago. It has taken many years to afford to use non-irritant materials little by little. It is all finished now (more or less) and we are already noticing a difference in warmth.

Easy to cut with a 10inch kitchen knife. I sharpen it on the band sander which leaves a slightly rough finish. Goes through rockwool like butter.

You can buy the proper knife to cut it, if you need to cut the roll to the correct width, keep the wrapping on and use a fine toothed wood saw, if you use a felt tipped pen, you can mark it by just rolling it along the floor, a bread knife is good for trimming but it depends on the type of the edge, wavy is best, if its like a saw blade it will catch and tear. As above, proper PPE is needed.

Thanks to all responders for your sound advice. All suggested PPE is on order, hoping to start installation early next week.

exile wrote: ↑Wed Nov 16, 2022 11:44 am Wear disposable overalls tucked into socks and hood up, gloves, a dust mask and goggles. You want to minimise contact with the fine fibres with your body - inside and out. It can be extremely irritant.

Very good advice .. it is horrible stuff. I forgot the dust mask 35 years ago when insulating and have had some lung problems over the years due to inhaling minute fibres at that time.

I installed hundreds of rolls or panels of glass wool. To cut, I mark each side with a marker pen, adding 1 or 2 cm to avoid thermal bridges. Then I line up a 10 cm wide aluminum ruler on my markings and press it hard with my weight to crush the material: left hand in front and right knee in back (if you are left-handed, do the reverse). With a stanley knife, blade fully extended and at 45°, I guide the blade along the edge of the ruler, gently and in several passes if necessary. The cut is clean and square with very little dust. And it works for any type of insulation and any thickness (even 20 cm or more)! Don't worry: once the ruler is removed, the insulation quickly returns to its normal thickness! Of course, in order not to damage the blade of the cutter and/or the floor, it is prudent to place a scrap of plasterboard, plywood or cardboard underneath the insulation.

@ Veem, just in case you don't mind using translate google or deepl (Dutch -- > English) a concise summary about the insulation of your French house. Many self explaining pictures. Keep warm......

Thank you for those last two replies. It was actually Biggles who posted the OP under my name but he has now joined the forum and will, I hope, get back to you. I'm also hoping we might stumble across someone who can do the work for us. If you were closer Biloute our search would have begun with you. Disposable overalls and proper masks have now arrived, so just goggles to come and then he'll be wanting to make a start.