Garage/Carport conversion...

Zulu

Folks I'm starting a DIY project to convert a brick built garage (separate to house) into a workshop/office. In years to come this will be a play room for the kids. My plan is to do most of the heavy lifting myself and to do it in stages.

Stage 1: insulate and floor attic space for storage. This will give me immediate storage. I'm going to do that this weekend.

Stage 2: insulated plaster board and skim walls.

Stage 3: floor.

I'm hoping you good folk might offer advice as I go...


So, tonight I'm going over to B&Q to buy "Knauf Eko Roll Loft insulation 200mm" which is on special at 3 for €60. By my calcs, 3 roll will do me. I'll lay it down between the joists, and then I've an old wooden floor I recycled from my dads house which I'll run across the joists to "floor" the space.

I reckon this is sufficient insulation for my needs, and the floor will only be used for storage so should be fine.

I'd greatly appreciate it if you'd call out any blunders I might be making... (or provide any tips/tricks).

Thanks.

(Attaching images for reference - picture and plan. Not shown in pic but in plan is a garage door)

listermint

Lovely Room to start with.


One key thing i will say to you and take it seriously . Air Tight Tape , Air Tight Membrane. Its actually a cheap item with massive long term benefits for comfort level when coupled with insulation. Ceilings, Walls Floors.

bfclancy

How you planning to keep the insulation up in the ceiling, plastic or plasterboard?

GreeBo

What depth are your roof joists?
If you are using 200mm insulation and want to also floor, you will need to get some stilts/extensions to allow you to floor without compressing the insulation.

+1 on airtightness.

Zulu

Firstly thanks folks for replying...

listermint wrote: »

One key thing i will say to you and take it seriously . Air Tight Tape , Air Tight Membrane. Its actually a cheap item with massive long term benefits for comfort level when coupled with insulation. Ceilings, Walls Floors.

So the attic space (like in the house) is "breathable" insofar as there is a grill under the eves overhang which is open to outside, and air flows through. I've noticed that the staira to the attic in the house has tape all around the entrance - is this what you mean by air tight tape?
The room wont be airtight for the first few years as I'm planning on keeping the garage door in place until I've enough saved up to replace it with a window (and the saving up is for a window a 4M lift and slide for the wall in the photo).

I'll do some research on air tight membranes....

bfclancy wrote: »

How you planning to keep the insulation up in the ceiling, plastic or plasterboard?

There's a plasterboard ceiling in place inside. So I was just going to roll it out over that.

GreeBo wrote: »

What depth are your roof joists?
If you are using 200mm insulation and want to also floor, you will need to get some stilts/extensions to allow you to floor without compressing the insulation.

+1 on airtightness.

So the joists are 2 by 6 inch. So, good call, you're right, I'd be compressing the insulation.

Options are stilts, which will loose me some storage.
Compress, which will loose me some insulation.
Or go with 100mm insulation instead, which will also loose me insulation...

How bad compressing it though? I know I'll loose some of the insulating value, but is it that terrible?

GreeBo

Zulu wrote: »

Firstly thanks folks for replying...
So the attic space (like in the house) is "breathable" insofar as there is a grill under the eves overhang which is open to outside, and air flows through. I've noticed that the staira to the attic in the house has tape all around the entrance - is this what you mean by air tight tape?
The room wont be airtight for the first few years as I'm planning on keeping the garage door in place until I've enough saved up to replace it with a window (and the saving up is for a window a 4M lift and slide for the wall in the photo).

I'll do some research on air tight membranes....

There's a plasterboard ceiling in place inside. So I was just going to roll it out over that.

So the joists are 2 by 6 inch. So, good call, you're right, I'd be compressing the insulation.

Options are stilts, which will loose me some storage.
Compress, which will loose me some insulation.
Or go with 100mm insulation instead, which will also loose me insulation...

How bad compressing it though? I know I'll loose some of the insulating value, but is it that terrible?

6" is around 150mm so you will be reducing your insulation effectiveness by 25%.


If there is already a plasterboard ceiling it more than likely doesnt have an air barrier, you *might* have enough access to tape joints especially where the ceiling meets the wall, but you probably dont...

For the sake of a better job and not that much (extra) work, would you consider pulling down the existing ceiling?
That way you could fit a membrane and tape, use 50mm insulated plasterboard slabs and not have to worry about compressing the insulation in the attic.... (since the 50mm boards will compensate for that...)
You will also be able to get a good seal between the walls and the ceiling...which brings me nicely to...what are your plans for the floor?
I presume the slab isnt insulated?

Sleepy

What will the heat source be once you've insulated the building and how often will it be used? Almost 80% of the insulative value of loft roll is in the first 150mm of insulation so if it's a room that's only going to see occasional use and won't cost a huge amount to heat, I'd be inclined to just get the 150mm rolls.

Zulu

Sleepy wrote: »

What will the heat source be once you've insulated the building and how often will it be used? Almost 80% of the insulative value of loft roll is in the first 150mm of insulation so if it's a room that's only going to see occasional use and won't cost a huge amount to heat, I'd be inclined to just get the 150mm rolls.

Yeah, it's hard to call usage. It'll be my office until the kids are older, and then a place for them to escape to - but thats in 6-8 years. I'll use it a bit, but not too much. It's outside the house so I'm not going to be disappearing....
In terms of heating PC's, and electric patio heaters are providing the heat presently and they work quite well. When the room is finished I'll use a oil filled electric heater (and will consider a stove in time).

GreeBo wrote: »

6" is around 150mm so you will be reducing your insulation effectiveness by 25%.

If there is already a plasterboard ceiling it more than likely doesnt have an air barrier, you *might* have enough access to tape joints especially where the ceiling meets the wall, but you probably dont...

For the sake of a better job and not that much (extra) work, would you consider pulling down the existing ceiling?
That way you could fit a membrane and tape, use 50mm insulated plasterboard slabs and not have to worry about compressing the insulation in the attic.... (since the 50mm boards will compensate for that...)
You will also be able to get a good seal between the walls and the ceiling...which brings me nicely to...what are your plans for the floor?
I presume the slab isnt insulated?

Humm I'm very reluctant to pull down the existing ceiling tbh. There is a cost aspect to this - I'm shoestring budget. I appreciate you're setting out a much better job, but you know, the ceiliing is there...

As for the floor, its concrete. I can see a damp proof membrane but I doubt it's insulated. I was planning on laying down standard 3mm foil woodenfloor underlay (I've enough left over from my dads new floor) and floating the cheapest laminate over that. Nothing fancy, as I'm conscious that it may well all come up in a few years when the large sliding door I'm saving for goes in.

GreeBo

Zulu wrote: »

Humm I'm very reluctant to pull down the existing ceiling tbh. There is a cost aspect to this - I'm shoestring budget. I appreciate you're setting out a much better job, but you know, the ceiliing is there...

Yeah I hear that, but if you are going to be boarding the walls and getting them skimmed anyway then the incremental cost is pretty low so you'd be getting a lot of bang for your buck!

Zulu wrote: »

As for the floor, its concrete. I can see a damp proof membrane but I doubt it's insulated. I was planning on laying down standard 3mm foil woodenfloor underlay (I've enough left over from my dads new floor) and floating the cheapest laminate over that. Nothing fancy, as I'm conscious that it may well all come up in a few years when the large sliding door I'm saving for goes in.

I'd worry that that floor would be very cold so...then again if you are in there today without issue then....

When you turn it into a kids play area you will likely need to address it though...

Zulu

GreeBo wrote: »

Yeah I hear that, but if you are going to be boarding the walls and getting them skimmed anyway then the incremental cost is pretty low so you'd be getting a lot of bang for your buck!

humm, you're killin' me. I hear you though....

I'd worry that that floor would be very cold so...then again if you are in there today without issue then....

Yeah the floor is cold, but I was going to live with it. I presume the alternative is to raise the floor with floor joists and insulate in-between?

When you turn it into a kids play area you will likely need to address it though...

True, and I'll have more time to save up!!

Sleepy

Honestly, I'd try and keep it as a shoe-string job, I've seen many of these conversions done but few of them get the level of use the owner had initially intended of them.

I'd keep the ceiling as is, insulate with 150mm loft roll, board and tape the walls with the warm board to save on the cost of a plaster (unless you're able to skim coat yourself?) and stick with the original plan for the flooring. I can't see the heating costs being exorbitant (particularly if there's a couple of kids running around in it or PCs running in it). It shouldn't be difficult to monitor the power use on that spur either so you should be able to make a better decision regarding any additional improvements with that data in hand.

keithdub

I would side with sleepy here. Hearing it isn't a huge issue once you have some insulation in it and a small heater in it I'm sure your kids will be happy playing in it (kids never feel the cold anyway) If I were you I would consider doing the big works first and wire slab and skim or tape and joint.

listermint

Feck that make it how you want. If your going to be spending 9 hours a day working in it then I'd fit it out exactly as I see fit.

LenWoods

Nice project there;
I've been reading through the posts and I see your planning to fit some insulated plasterboard sheets to the walls; I've done this job myself in our bedroom when fitting a television on the neighbouring wall of our semi detached house I fitted a 1.5" flexible PVC drain pipe purchased from woodies and run it from the attic space down the wall of the room to house the television cables,
Rather than chasing in to the wall we fitted insulated plasterboard over the pipe,
We found a see-saw method to ensure the sheets stay tight to the ceiling when fitted;
You cann see it in pictures here on my DIY home improvement thread which is now in its embarrassing fourth year in progress but it has expanded to the entire house where it was initially supported to be just the living room
were doing it without any loans much the same as you said your converting your garage,
Anyway heres a link to the progress in Bedroom 02 showing the radiator fitting first which is irrelevant here followed by the insulated plasterboard fitting which may be of interest to you:

https://www.fordownersclub.com/forums/topic/80864-living-room-project/?do=findComment&comment=716250

Theres also information about pre-varnished oak wooden window sills on page one of the thread may also be of interest.

Zulu

Thanks all for you contributions.

I went with 170mm in the end, but could have gotten away with 200mm (unless it expands further over time).
Got it down in jig time, and recycled floor over it. Great storage...



Lessons:

It isn't "precut", only the first layer is.

Don't take it out of the wrapper in one go at the start, but peal the plastic back as you need it.
Stanley was way better at cutting it than a saw.
Have a pole handy to poke it into tight corners.


Attaching pics of progress, cause I'm delighted with myself....


I'll update again when I get to the walls, unless there's an order to this I'm missing?

Zulu

So I'm looking to price up the plaster boards. I reckon 13 will do me for the wall (excluding garage door). Any thoughts on what dept of insulation I should be considering?

Looks to be a fair difference in price (from 102mm at €70 to 50mm at €36). I appreciate that theres 5cm being taken from the room either side in the difference, and doubling the price. Is the 100mm really worth it?

GreeBo

The thicker the board the more *sound* insulation/isolation you will get...might not be an issue for a garage-office.

/edit
apologies, I half read your post and thought you were talking about thickness of plasterboard!

Are you planning on buying insulated boards or separate insulation?

Zulu

GreeBo wrote: »

The thicker the board the more *sound* insulation/isolation you will get...might not be an issue for a garage-office.

/edit
apologies, I half read your post and thought you were talking about thickness of plasterboard!

Are you planning on buying insulated boards or separate insulation?

Insulated boards - figured it'd be the handiest...


So I've decided to plow on with the big lift and slide and was pricing up my options. It's a 4.5m span, so it'll be costly. Looking around the 7K mark. That'd be a 2 panel aluminum. But I've been advised that I could do a 3 panel pvc for cheaper (a lot cheaper).
Any thoughts folks?



Also, I know I'll need to fit and RSJ which I was going to also do myself. Doing some research online, it doesn't look too bad, and I can get men to lift it for me on the day. Do I really need to engage an engineer here? Surely I can just over-spec the steal and be fine... ...surely?

listermint

Zulu wrote: »

Insulated boards - figured it'd be the handiest...


So I've decided to plow on with the big lift and slide and was pricing up my options. It's a 4.5m span, so it'll be costly. Looking around the 7K mark. That'd be a 2 panel aluminum. But I've been advised that I could do a 3 panel pvc for cheaper (a lot cheaper).
Any thoughts folks?



Also, I know I'll need to fit and RSJ which I was going to also do myself. Doing some research online, it doesn't look too bad, and I can get men to lift it for me on the day. Do I really need to engage an engineer here? Surely I can just over-spec the steal and be fine... ...surely?

There's a wholesaler on done deal that gets slides in regularly. Drop him a line could be considerably cheaper.

Zulu

listermint wrote: »

There's a wholesaler on done deal that gets slides in regularly. Drop him a line could be considerably cheaper.

Sound, can you pm his link/ad please?

Zulu

Big thanks listermint.
Not sure if I found the guy you are on about, but I reached out to one crowd and they were a lot cheaper. Looking more like €4,500 so saving me €2,500!!!

Incredible.

Zulu

Right! So got chatting to a friend whos an engineer and he's kindly done the maths on the steel for me.

I've 2 potions - 5m long box section beam (200x200x5) or I-beam (203x133x25).
The box would be heaviest at 150Kg, but altogether a lot smaller and lighter than I was expecting.
Box looks to be ~€320 delivered with I-beam ~€220.

SO. Box would be easier for finishing, so I'm inclined to spend the extra €100. I've to do some research on what that "finishing" will look like.

Any thoughts/considerations/ideas folks?