New (to me) garage for workshop

[craigs]

Lets try this in a correct forum...

Morning chaps,

Hope we are all well?

I have been searching a fair bit and can't quite figure out how to do my soon to have garage workshop. Its' a single garage with eaves. I was thinking of the following:

Plasterboard-ing the ceiling joists with insulation above it and boards for storage (as we have no loft in the house)

Flooring

Option 1
Laying 50mm celotex/kingspan on the floor and taping it together into a large panel then moisture resistant chipboard floor panels on top so it all just floats << will this stand up to planned purchases like tablesaw/bandsaw/planer/thicknesser?

Option 2

screwing down 3x2's with enough distance to lay celotex/kingspan between the joists and same chipboard floor boards on top

Questions on this:

Would sheet ply be a better choice for floor cover given is got to hold decent weight?

Do I put a poly sheet damp course? if so directly on the concrete floor or draped over the joists (so any screw piercings are higher than the base concrete) ?

Walls:

Was thinking to do the same as gosforth handyman, 3x2 cls verticals with 50mm insulation and 18mm mdf on top.

The garage door will be covered with a "bolt-on" stud wall made from 3x2 frame, 12mm mdf and same 50mm insulation. if i need a big delivery i can unbolt it and move it out the way to open the garage door (theres a side door for access)

Does this all seem feasible?

Floor first then walls?

Im trying to keep it as soundproof as possible so i don't annoy the new neighbours. I also want to keep cost as low as possible as im going to have enough to shell out for with a new home so any material suggestions would be welcome.

Cheers
Craig

 

[Sheptonphil]

Plasterboard-ing the ceiling joists with insulation above it and boards for storage (as we have no loft in the house)

Flooring

Option 1
Laying 50mm celotex/kingspan on the floor and taping it together into a large panel then moisture resistant chipboard floor panels on top so it all just floats << will this stand up to planned purchases like tablesaw/bandsaw/planer/thicknesser?

The ceiling option is exactly what I am doing in my new purpose built workshop. Min 200mm insulation, vapour control membrane on the room side of joists and then plasterboard with access hatch to loft space.

Your option one floor will work, it again exactly what I’m using, 50mm celotex, 22mm P5 moisture resistant chipboard floor boards. I will be using a 16” bandsaw, table saw, 350kg lathe, pillar drill and a substantial workbench on the floor. The boards will be fine. Does the existing floor already have a DPM to keep it dry, I suspect it probably has.

 

[DBT85]

For keeping costs down, keep an eye out for seconds or unused insulation.

Apart from that listen to Phil, he's already doing most of what you want!

I'd guess most of your noise right now will escape via the roof and the garage door. With those covered and insulated it should do a good enough job. Maybe don't fire up the tablesaw at 1am :lol:

 

[craigs]

Thanks chaps,

Just wanted to make sure i was going about it the right way. wheres a good place to look for 2nds on insulation? that will cut cost a little i guess

Are there any specific models of celotex to use? it seems there is a pretty big range of the stuff.

cheers,
Craig

 

[MikeG.]

An alternative to a plastic VCL under the joists is to use foil backed plasterboard.

Insulation above the joists can be mineral wool/ fibreglass. It's a much nicer product these days (buy the brown stuff). For celotex in the walls and under the floor go to one of the seconds suppliers. It's pointless buying expensive sheets from a builders merchant when there are a number of seconds suppliers around the country selling it for around half price.

The biggest deal with getting a garage warm is dealing with the door. Focus your efforts there.

Walls.......18mm MDF is pointless and expensive. 9 or 11mm OSB is perfect for the job, but paint it white immediately (ie before you move anything into the space). Personally I favour fixing such insulation in 2 or 3 layers...the first with battens running vertically, and insulation between, the second with battens horizontally, insulation between, and if you want a third you can just fly straight over the second with full sheets of insulation(but mark where the battens are otherwise fixing your internal boarding is a nightmare!). You do a much better job of fixing, and much easier, screwing 25mm stuff to the wall than trying to screw 50mm stuff.

 

[craigs]

Thanks mike,

I was looking at the roll stuff for the ceiling, just to keep the cost down a bit, i didnt think of foil backed pasterboard, nut thats a good shout.

For the walls, 2 layers of 25mm celotex? will that be much different to 1 x 50mm layer?

Ill definitely go with OSB as it will also save some sheckles.

 

[MikeG.]

It's the ease of fixing that's the difference between 2 x 25 or 1 x 50 Celotex. So much easier using roofing battens. The insulation value is much the same, and more depends on how well you do it (no gaps etc).