Garage to Workshop Conversion

[jedmc571]

Hello All,

I know this gets covered occasionaly, but with available products and ideas changing all the time, I just wanted some up to date ideas. I've been in the house for 3 years and never really considered it an area to work from other than little jobs, but recently after emptying it to have cavity wall insulation, I realised it's potential.

I have a single garage 19 X 8 approx attached to the house with access via an up and over , and through the kitchen internally.
The roof is sloped with a small hip at the front,with concrete tiles, the wall on the house side is blockwork with cavity with cavity insulation ( blown in type installed yesterday ) and the other wall is a single skin brick.
I am proposing the use of Quinntherm, same as Kingspan, but I work for Quinn and get discount,100mm for ceiling, and 50mm for the single skin wall, the party wall will be ok.
The roof void has joists going accrues and I use it for timber storage, but hoping to put some of my lesser used bits up there when it's warmer, after boarding it out a bit, with this in mind is it worth plasterboarding over the insulation? I know most of it would be unseen, but it would add to the insulation, and when painted would help reflect the light?
The walls will be finished with 18mm OSB, or possibly Chipboard (as I get chipboard free )
In general it's dry but cold, I need to tackle the issue of the garage door, I think that's where the problems will be, electrics will be upgraded with a separate ring main and consumer unit, so really it's dealing with the damned British weather.

Have I missed anything? or any suggestions about anything?

still looking at the floor,it's concrete but it slopes off about a foot from level towards the door, I think a false floor, that way if I ever sell it on it can be removed and used again, any other suggestions?

Then the other problem is having to fill it with "shine" machinery and the likes :lol:

Cheers

Jed

P.S A big thanks to Mike Garnham who suggested the materials and sizes for it all

 

[MikeG.]

Jed,

you don't need 18mm OSB on the walls. 10mm will be fine. You must paint it though (it helps glue the surface together, and really throws the light about)...........and as I have said a number of times on here, I wouldn't bother with plasterboard for a workshop wall. In my view it is too easily damaged.

Good luck..........look forward to the photos!

Mike

 

[jedmc571]

Cheers Mike,

Save me a few quid on the OSB :lol: do I need to use anything in particular to paint it with?

The plasterboard is over the insulation in the roof void only, or is it wasted money?

Cheers

Jed

 

[MikeG.]

Jed,

you're insulating at rafter level. The only reason to use plasterboard up there is for looks alone. I wouldn't bother!

Mike

 

[ciscoeuk]

if you want a few ideas for fitting ur your workshop i have a set of shopnotes that will help! i have used them to start to refit mine

pm and send email address for a full list.

i have a garage of the same size, some of the notes give you space saving ideas

photos on completion

all the best

 

[jedmc571]

cheers

PM sent!

 

[devonwoody]

Your biggest problem regarding insulation is the big garage door. You need it to get things in and out and sometimes long lengths of timber need the door open.

so you cannot seal out the draughts permanently, next if it faces the sun at any time its like a hot radiator in good weather when you dont need it and its like the inside of a fridge winter time.

If you seal the door frames the heat of the door attacks the sealing material.

Best of luck.

 

[Doug B]

Jed,
If you make a set of wooden garage doors that hinge out this maximises your internal space.
I did this, then put a sliding patio door behind the doors.
I`ve found this great, my alarm sensor is on the outside doors, so if anyone tries to break in the alarm goes off but they still aren`t in the workshop. I get very little sound transmission through the doors, keeps the neighbours happy & it keeps the shop nice & warm while still having a big enough door to get machines, projects in & out.
You can pick up patio doors cheap second hand , a simple timber frame makes up for oversized openings & allows the door to be removed if necessary.
Oh & it lets loads of light in when the wooden doors are open.

 

[MikeG.]

Good idea B.. I mean James, but there are a couple of things to bear in mind. Firstly, this won't be great if you ever use an angle grinder in your workshop, and secondly, if your table saw fence extends past the back edge of the saw blade I should make sure that it doesn't line up with the glazing!!

I suggested by PM that Jed might remove the up&over door from its frame and build a studwork wall outside it with a door built into it. That way, if he ever sells he can whip the wall out easily and just rehang the garage door.

Mike

 

[Doug B]

Good idea B.. I mean James, but there are a couple of things to bear in mind. Firstly, this won't be great if you ever use an angle grinder in your workshop, and secondly, if your table saw fence extends past the back edge of the saw blade I should make sure that it doesn't line up with the glazing!!

I suggested by PM that Jed might remove the up&over door from its frame and build a studwork wall outside it with a door built into it. That way, if he ever sells he can whip the wall out easily and just rehang the garage door.

Mike

use an angle grinder in MY workshop, sacrilege. Luckily patio doors have toughen glass, & even when trying to break them with a hammer put up stern resistance.
Your idea of a stud wall with door is a good one, but i do like the natural light the patio door lets in, as it`s my only source of natural light.
Both structures are easily removed.

 

[rjb]

I'm about to insulate my garage using Kingspan and OSB and the building is of similar construction to yours. I put a post on this forum recently to enquire about the best way to do this and there seemed to be two schools of thought. Most of the advice I received suggested that I should batten the brick walls to allow an air gap for ventillation behind the insulation, but I was then advised that I could fix the insulation and OSB directly to the brick walls. This seemed like an easier method so this is the way I planned to do it, but I have just spoken to a builder who is working on my house an he said it is really important to allow a ventillation gap otherwise I will have big problems with condensation and damp. So now I'm feeling slightly uncertain. I was just wondering whether you were planning to leave a ventillation gap and whether anyone had any further advice on the subject.

Regards,

Richard.

 

[CWatters]

If you want to do a proper conversion job you should probably think about condensation risk (eg on the underside of the sarking/membrane).

The proper way to do the roof would be to form a ventilated void between the insulation and underside of the membrane. This should be 50mm deep. There should be vents into this via the soffets and at the ridge. The vents at the eaves should have an area equivalent to a 10mm slot full length of the eaves. Half that area at the ridge using vent tiles. Should fill the rest of the rafter depth with insulation and put another layer underneath to bring the thickness of insulation to around 150mm. So if the rafters are 150mm deep you need 50mm ventilated air gap, 100mm Celotex between the rafters and 50mm celotex underneath them. Then either tape the joints or staple up a plastic vapour barrier and board/plasterboard. This construction also stands some chance of meeting the building regs.

Obviously you can skimp on this but it's upto you.

 

[CWatters]

RJB - I would.

The two issues are 1) warm damp air from the room getting through tiny gaps in wall and condensing on the cold wall. 2) water penetrating the outside brick skin. The cavity and ventilation helps with both. Modern cavity walls are ventilated (to a limited degree) using vertical vents/weep holes in the perps between bricks. See also my previous post.

 

[MikeG.]

RJB - I would.
The two issues are 1) warm damp air from the room getting through tiny gaps in wall and condensing on the cold wall. 2) water penetrating the outside brick skin.

I think that this risk is much more theoretical than real if the currently exposed workshop walls are dry (from external water penetration........forget condensation for a minute).

Both Stirling Board and Kingspan are highly impermeable to water vapour. Stagger the joints, or use battens to form the joints, and I would suggest that the potential dangers of condensation on the inside of the brickwork is virtually nil.

If you do suffer, or potentially suffer, from water penetration from the outside, then you should certainly ventilate behind your insulation (as I described in a thread the other day regarding insulation within a cellar).

Don't forget that to create an unventilated void is the worst of all worlds.

Finally, at the risk of raising the ire of one or two.......don't listen to builders too much! There are always subtleties and variations which may dictate a completely different detail or technique from the one they seemingly did in similar circumstances on the last job.

Mike