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100mm Celotex rigid insulation board installation advice and tips?

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Rob Cheetham

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Clevett doesn’t have to pay for it thats why he uses it…..
just use a long Bosch jigsaw blade.
any gaps foam them trim it off once dried and silver tape it.
Just got them soft material bosch blades of amazon. They are massive. I have read reviews thought that they can wonder on the bottom edge. One review said to angle grind one a bit shorter so it just protrudes the bottom of the 100mm board. Im not sure but thinkingI will defo use a straight edge clamped to the board to run the jigsaw along. May help keepit steady. Also got one of them surform block planes to shave off little bits to make fit.

What are your thoughts on them?
 

JobandKnock

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Im not sure but thinkingI will defo use a straight edge clamped to the board to run the jigsaw along. May help keepit steady.
Tried jigsaws a while back when we had some wierd recycled wood soiund insulation from Germany - the blades wander too weasily and they make quite a bit of mess. There's a little trick we show the apprentices to cut the stuff with a hand saw when they are starting - drop a 4 x 2 onto the face of the material and use it as a guide to cut to about 2in deep. Flip it up on its' edge then use the deeper guide to saw the whole way through. A bit slower than making a single cut, but can be done in situ somewhere like an attic and most importantly it delivers a square cut. For my own use I have a wavy blade insulation saw {sorry, Jacob) which cuts with less mess and less wander than a standard hand saw does. On thinner materials I tend to use an insulation knife rather than a saw (looks like a bread knife, but isn't) which is also handy for doing trimming cuts around pipes, etc. Can't say that I could justify lugging power tools, benches, etc around unless I was doing a heck of a lot of insulation.

Also got one of them surform block planes to shave off little bits to make fit.
Have you actually tried a Surform on Cellotex/Kingspan? Unless the blade is brand new it won't cut and even then it probably won't cut that well. If you need to shave bits off a hand saw will do the task quickly and efficiently, but ideally you want to avoid this

I'm lothe to admit this, but Jacob is probably right when he says that hand tools make complete sense doing this job unless you are insulating a sports stadium... With insulation you are often working in confined spaces with limited ventilation so the very last thing you want to do is make loads of dust - and even hand sawing PUR insulation makes loads of airborne dust - so there are other reasons for not going "high tech" (other than the £600 odd bill for a Festool)
 

owen

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Have you actually tried a Surform on Cellotex/Kingspan? Unless the blade is brand new it won't cut and even then it probably won't cut that well. If you need to shave bits off a hand saw will do the task quickly and efficiently, but ideally you want to avoid this
Have you actually tried a surform on it? They work a lot better than you'd imagine, far better than shaving bits off with a handsaw, handsaws tend to rip the silver foil face too.
 

Denty

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Just got them soft material bosch blades of amazon. They are massive. I have read reviews thought that they can wonder on the bottom edge. One review said to angle grind one a bit shorter so it just protrudes the bottom of the 100mm board. Im not sure but thinkingI will defo use a straight edge clamped to the board to run the jigsaw along. May help keepit steady. Also got one of them surform block planes to shave off little bits to make fit.

What are your thoughts on them?
Never had a problem with them myself, yes we use a straight edge has well.
if you’re ok with a saw using a straight edge will get you the same result.
never used a surform but I would expect a lot of dust and if I’m honest I would only do it outside unless you have a very good face fit mask.
 
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Spectric

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Could you explain this a bit more pleas not sure what you mean lol. Thanks
With electrical wiring during the design you have to derate a cable if it is run within insulation, the opposite is true if it is surface mounted or run on a cable tray. In the regs you have tables that give you correction factors for several parameters, so you may end up with a 4mm cable and then due to corrections, ie it is within insulation then you may need 6mm.

Table 6B in the site guide will give derating values, best option is not to run cables within insulation.
,
 

Jacob

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,,,,,,,,,,,,. For my own use I have a wavy blade insulation saw {sorry, Jacob) which cuts with less mess and less wander than a standard hand saw does.
Didn't know they existed, looks a good idea but I found a handsaw perfectly OK
.....
Have you actually tried a Surform on Cellotex/Kingspan?
Yes, they don't work.
If you need to shave bits off a hand saw will do the task quickly and efficiently, but ideally you want to avoid this
Everybody makes mistakes - not least because rafters or ceiling joists may not be as straight as thought. Hand saw again , or bread knife
I'm lothe to admit this, but Jacob is probably right
Gets said surprisingly often :ROFLMAO:
when he says that hand tools make complete sense doing this job unless you are insulating a sports stadium... With insulation you are often working in confined spaces with limited ventilation so the very last thing you want to do is make loads of dust - and even hand sawing PUR insulation makes loads of airborne dust - so there are other reasons for not going "high tech" (other than the £600 odd bill for a Festool)
Track saws obviously a good idea but not for everything. Overkill for insulation, like cutting weetabix with an axe!
 
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Stuart Moffat

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You are going to keep saying that tracksaws are no good for this until you have the last word I guess. But it doesn’t make it any truer than the first time you said it.
 

JobandKnock

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Have you actually tried a surform on it? They work a lot better than you'd imagine, far better than shaving bits off with a handsaw, handsaws tend to rip the silver foil face too.
I rarely need to shave them to get a good fit, and Surforms create dust which when working in confined spaces is a major issue. And in any case a Surform is just another piece of (relatively useless) kit to drag around which will rarely get used - something which you become sensitive to when you spend your life dragging tool kits around buildings
 

owen

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Surforms DO work, and work well on it for straightening out dodgy cuts.
 

owen

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I rarely need to shave them to get a good fit, and Surforms create dust which when working in confined spaces is a major issue. And in any case a Surform is just another piece of (relatively useless) kit to drag around which will rarely get used - something which you become sensitive to when you spend your life dragging tool kits around buildings
🤣 It's hardly a heavy bit of kit 🤣
 

JobandKnock

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Gets said surprisingly often :ROFLMAO:
It was written tongue in cheek - you know where I'm coming from, I'm sure

Track saws obviously a good idea but not for everything. Overkill for insulation, like cutting weetabix with an axe!
Yes. A lot of solutions here which seem to be theory without practical experience. When you are putting in insulation and fire stopping yoiu are often working in very confined spaces with poor lighting and minimal ventilation. That makes dust suppression a number one priority, so you wear an FFP3 mask. Some insulation is intensely irritating on the skin (e.g. older mineral woold) and most of it is a respiratory irritant (including PUR type materials) so you want to avoid shaving bits off, etc and generally making dust where you can as it will contiminate your clothing (and eventually your van), Cutting on a table is all well and good, but at least for some of the time would involve having two guys doing the job - wasteful of man power - or constantly climbing up and down all day long - which be becomes really tiring and a potential accident risk. I can see a use for the Festool saw in some trade environments where you are doing mass installation of, say inner stud wall insulation on a housing estate, but it just isn't worth it for many jobs
 

owen

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I guess it's comes down to....

Tracksaws cut faster more accurately and are very much dust free, can be cut on the stack to avoid moving boards around.

Handsaw cut slower, require boards marking out with a straight edge are very dusty, and require boards being repositioned for each cut.

I know which works best for me, I cut hundreds of sheets each year not just enough for insulating a garden shed.
 

JobandKnock

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🤣 It's hardly a heavy bit of kit 🤣
It's weight plus volume which are the issues, which anyone on site based work should understand. TBH in site joinery work a Surform is almost useless for me and many others - the only time you see them is when it's necessary to board out (plasterboard) and even there Marshalltown make far better alternative.

You have your way of doing things - it doesn't work for me, nor seemingly the many people who've worked with or for me over many years
 

Jacob

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You are going to keep saying that tracksaws are no good for this until you have the last word I guess. But it doesn’t make it any truer than the first time you said it.
No it hasn't got any truer it's still just as true as the first time I said it. I didn't say "they are no good" I said it's a lot easier, quieter and less dusty with a hand saw.
And you only have to cut once! The idea that you cut half way with a track saw and then finish with a hand saw seems to be particularly pointless.
Then there's the dust extraction, extensions leads, humping them from room to room etc.
 
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owen

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It's weight plus volume which are the issues, which anyone on site based work should understand. TBH in site joinery work a Surform is almost useless for me and many others - the only time you see them is when it's necessary to board out (plasterboard) and even there Marshalltown make far better alternative.

You have your way of doing things - it doesn't work for me, nor seemingly the many people who've worked with or for me over many years
I do understand, but my site work is based on property renovation of larger properties than new builds so I guess I spend more time in one place than most. Yes those are the two things I use a surform for, tidying up plasterboard and tidying up kingspan if needed. Sure I can work without it, but having it makes life easier for me atleast.
 

owen

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No it hasn't got any truer it's still just as true as the first time I said it. I didn't say "they are no good" I said it's a lot easier, quieter and less dusty with a hand saw.
And you only have to cut once! The idea that you cut half way with a track saw and then finish with a hand saw seems to be particularly pointless.
Then there's the dust extraction, extensions leads, humping them from room to room etc.
Less dusty? You've obviously never ever ever used a tracksaw with dust extraction to cut insulation if you think they're less dusty.
 

Hanman-Tools

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I have always used a wavy edged bread knife with a straight edge, very little mess and doing it all the time it is quite accurate.
 

Jacob

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Less dusty? You've obviously never ever ever used a tracksaw with dust extraction to cut insulation if you think they're less dusty.
Oh all right :rolleyes: . To put it another way; you don't need dust extraction with a hand saw. Though frequent sweeping and hoovering would be good - you get a bit of dust but most of it is crumbs. Not having a motorised tool blasting the stuff about is helpful.
It's not a competition Owen you can do it how you like. I'm just saying how I used you do it and why.
 
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