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I've just moved into a new house that has a workshop attached to it which I plan on using for my guitar building. At the moment, it just has bare breeze block walls (apart from the one joining the house) and a fibreglass (I think) roof. It is fairly close to the house next door as well, so I'd like to acoustically insulate it as well as thermal insulation. What I've been thinking so far is putting up fibreglass batt insulation on the walls and roof like this http://www.insulationexpress.co.uk/Acou ... -Roll-.htm between timber joists and sheathing the whole thing in 12mm ply or OSB. Is that a good idea? I have absolutely no experience with this sort of thing at all, so I'm just looking for a second opinion.
There's a picture of the workshop on my facebook page, below. It's 6x3m.

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"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Fiberglass batting needs to be placed between wall studs to prevent compression which will make the insulation value useless. If you have no studs, rigid foam board would would be a better idea.

That's what I meant by joists. I would screw them to the wall first and screw the sheathing to them.

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"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

I would put 1" rigid foam insulation on the block wall with the appropriate adhesive, then put wall studs (joists) with the fibreglass, and a vapour barrier under your choice of sheathing. OSB will work, but it isn't fire resistant.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Joists are horizontal floor or ceiling members. Vertical members in walls are called studs.

Ok thanks. I'm not really up on building terminology.

do you mean fix the studs to the foam? That doesn't sound very strong. Would plastic sheeting do as a barrier? And would plasterboard be better for sheathing? Could you still hang stuff on it?

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

The stud wall consists of the vertical studs, and a horizontal top plate and foot plate. The top plate is attached to the ceiling joists, and the foot plate is attached to the floor, with the studs spaced 16" on center. I wouldn't attach the studs directly to the block wall regardless of what you decide to do-there should be a gap between the two. The vapour barrier should be whatever building code in the UK calls for. Here it is 6mil.
Plaster board would be best. It is fire resistant, smooth, inexpensive, and paints well. This might help.http://wiki.diyfaq.org.uk/index.php?title=Stud_wall

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Peter, Great looking design and workmanship on your face book guitars.

For your work shop I would put up a 2x4 stud wall against the cinder block wall. That will give you room to run electrical and insulate. I don’t thing I would worry about acoustic insulation in that wall. With the cinder block just putting in R13 or 15 insulation should do the trick. In regards to moisture barrier I’d be careful. A plastic film will end up keeping more moisture in than it keeps out. If required by code you may want to put up something like Tyvek on the outside of the new wall. That will keep water out while it allows vapor to pass through. (avoiding mildew in the process) You could cover the inside of the new wall with sheetrock (gypsum board), that will add to the acoustic and thermal insulation.

Most of the acoustic and thermal loss of the room will be the ceiling. I would insulate that with a R-37 or 39, or as thick as you have space for. (don’t compress the insulation) If you have vents to the outside were the rafters meet the cinder blocks you will need to put in baffles (Paper or foam, very cheap) to allow air to circulate between the insulation and the roof.

On the clapboard side (I’m guessing home) you can put some foam board up if you desire.

Look luck and get to building those beautiful instruments!!!

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Joe Beaver
Maker of Sawdust

Hi Peter,

I can't add anything to the advise you've been given. However, I visited your FB site and want to compliment you on your instruments. You've done a great job...never know you were a beginner if I hadn't watched your first build on the OLF
I too want to make a cajone, and wondered where you got the plans?

Cheers and happy building! Beth
Edit: oops, this was supposed to be a PM...sorry for the hijack!

Thanks very much for the advice. I don't believe there are any vents in the roof/wall joint. Does that matter?

Beth, thanks! For the cajon, I sort of followed these instructions: http://www.thecajondrumshop.com/?page=H ... ld-A-Cajon. I just used whatever materials I had, so used 6mm ply instead of 12mm for the back and sides. To compensate, I put in a frame going all around each edge. I think next time I'll use 9mm as a compromise. That one is a bit too snary (is that a word?) and I think it resonates too much with the thin sides.

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

When I replaced my workshop roof a couple of years ago I used multi-layer foil insulation - it's more expensive, but takes up less space and is very easy to work with. Something like this stuff:
http://www.roofingsuperstore.co.uk/prod ... ation.html

James

Roof vents are a must if you are going to insulate, Peter, otherwise moisture will build up with no way to escape.

Alex

_________________
"Indecision is the key to flexibility" .... Bumper sticker

The vents between the rafters are intended to vent an attic space above the ceiling. You won't have an attic unless you put a ceiling in. What you have is a cathedral ceiling and it is normal to have no vents. The only down side is the sun will heat the roof up a little higher than normal because of the insulation causing petroleum based roofing material to wear out a little sooner.

The room should not be closed up for long periods of time when the humidity is up. Two windows open an inch or two should do it.

PS: After looking some more at your shop photo I see you have a slab on grade. Most likely it doesn't have a moisture barrier under the slab (as evidenced by the darker coloration of the slab), so keeping the RF reasonable in the work area is something you will need to address. You probably will need a dehumidifier for the room.

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Joe Beaver
Maker of Sawdust

Ok, I've been doing some reading online and it seems some people say you don't need vents and some say it's an absolute must - great, the joys of the internet! I'm definitely putting a dehumidifier in there. I'm right on the west coast of Wales, so it's usually in the 80's or 90's. What do you mean by a slab on grade?

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"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

[/quote]
What do you mean by a slab on grade?[/quote]
It appears the floor is a concrete slab placed on dirt. Hopefully it will be on grade (three or more inches above the surrounding outside grade. If it is below grade, as in a basement, then it will present a different problem with a different solution, namely waterproofing the outside of the wall to below the slab level and a French drain. If it is below grade that may have already been done.

If it was a slab under a house these days it would have 5 or 6 mil plastic under the slab and above the dirt. That is to stop moisture from moving up into the slab and then evaporating into your work shop. Since yours has the dark blotchiness about it, it probably has no plastic under it. Hence it will be a constant source of moisture in the shop. With ventilation or a dehumidifier it should be no problem.

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Joe Beaver
Maker of Sawdust

PeterF pop over to the ukworkshop forum, there are lots of really good workshop builds there which really helped when i built mine.

Sent from my KFTT using Tapatalk HD

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Nick

Follow my musings on getting started in luthiery http://www.tredwellinstruments.co.uk