My garage

[wilfy]

we've recently moved in to this house, and part of the criteria for us moving was that i had a garage for all my tools and for me to have a place to work on my hobbies and slowly build up my collection of tools which will peak with the build of my cnc machine at the start of next year.

now the choice of how the garage has been built is not my choice as i'd have had brick built over this any day, but either way its at least 20 times bigger than the outhouse i worked out of at our previous house.

started off like this

as a storage place while we moved, believe me the amount of crap I've shifted out of that garage the last few weeks has been depressing



so today i got started on cladding it out, material of choice is BnQ's OSB 2 11mm board, all cut to size and delivered to the garage all i have to do is simply drill a few holes and it's done

all cleaned out ready to clad

I've had problems drilling the concrete garage as i believe it's steel reinforced so it's pot luck if i hit any metal.. i hit something today i'm it melted the bit square off, so i'm borrowing an SDS this week which will hopefully help get it done


the funky flooring is actually some cheapo outdoor play mats that Tesco were floggin off for £3.50 per pack of 4, i'd always said i wanted a padded floor due to bad knees so i'll never have to worry about where i'm kneeling down, plus i plan to do some exercise in here as well so it's multi purpose it also has the added benefit of being soft on the feet so when standing still for ages it wont be a cold concrete floor beneath me. i actually like the fact it's coloured :D


future plans are 2 x 25mm mdf worktops which to start with will be mounted on some timber frames, but i would like to make steel box section frames and bolt them down to the floor so i can mount a vice on one and have better stability. at the end of one work top will be the mig welder I've just bought, the end of the other one will be a table saw. the cnc i plan to build will basically take up the space of a 2x2 square of the flooring.

i also plan to have a weights bench in there as well, i may even make provisions to have this folding out the way so it doesn't take up too much room and a rack to hold my homebrew kegs, one of which is pictured in the first picture

[irving2008]

Nice garage. Be very careful about drilling into the reinforcing rods, you can easily crack the concrete. Even a hairline crack will allow moisture in and will cause spalling (flaking of the concrete due to the rod rusting) and cutting through a rod could impact on the integrity of the panel.

Have you considered how to heat it in winter? The thermal conductivity of those concrete slabs is suprisingly high, it will be chilly in there in the winter, even with the OSB acting as sone insulation you'll need approx 4kW to maintain an internal temp of 20degC when its 0degC outside. Personally I would have glued 50mm battens to the concrete at suitable intervals, filled the gaps with 50mm insulation and then screwed the OSB to the battens. Would be quicker to install, and warmer.

What are you planning to do about the roof? Apart from the obvious gaps you can see due to the corrugations its also a major source of heat loss and needs at least 75mm insulation. Ditto the door.

I like the floor mats, but sadly I thnk they'll look very grubby soon. Are they washable?

[John S]

I'm with Irving on this, whilst you have chance fit some insulation, it will pay for itself over and over again. You can get some powdered adhesive used for sticking plasterboard to walls, cheap and it stick like shìt to the proverbial blanket.

Also second the floor tiles, I got some from Amazon a while ago and put some on the floor boards in the workshop. That's the boards that sit on a concrete floor in front of the bench, like duck boards but in my case just solid 25mm MDF to make it easier in your feet. Lasted a week before they had chips trod in and were starting to break up.

[m_c]

Irving, where did you get the info for calculating heat loss/heating requirements?

[irving2008]

Irving, where did you get the info for calculating heat loss/heating requirements?

Ummm, one of the civil engineering websites... IHeat Loss through Building Elements due to Transmission

but when I googled I also came up with this: Heat Loss Through Enclosure Walls Equations and Calculations - Engineers Edge which I've not tried to see if it gives the same answer.

Also I found stuff on the concrete supply industry website..

I was doing the calcs for my own proposed workshop and 75mm on the walls, 100mm in the roof and a DPC in the floor are almost essential... I reckon my 6m x 4m build (no up n over door and double glazed, with uPVC personnel door) will require only 600 - 800W to maintain temperature. Given I only have a 32A breaker on a 20A feed I don't want to be using 12A for a 3kw heater.. i want to be able to power everything with some margin. I also plan remote heating control so I can maintain a background temperature in there to ward off condensation and remotely bring it up to working temp fairly quickly

[m_c]

Thanks for that. I've tried googling for those figures/calcs in the past, and always given up due to finding totally irrelevant or overly techincal stuff that just makes my head hurt, but those pages simplify things well!

[irving2008]

Thanks for that. I've tried googling for those figures/calcs in the past, and always given up due to finding totally irrelevant or overly techincal stuff that just makes my head hurt, but those pages simplify things well!

Yes i found it useful as well

Sample calcs...

For a 5m x 2.5m concrete panel garage, 2m high. corrugated steel roof

Wall area = (5 + 5 + 2.5) * 2 = 25sq m. heat loss = U x A x dT . U = 1/R for concrete ~ .08/25mm so a 50mm panel R=0.16, U = 6.3, loss = 6.3 x 25 x (20 - 0) = 3150W
Up n over door = 2.5 x 2m = 5sq m. U of metal door = 6.8 Heat loss = 6.8 x 5 x (20 - 0) = 743W
Roof = 5m x 2.5m = 12.5sq m. U of corrugated metal = 8.5 Heat loss = 8.5 x 12.5 x (20 - 0) = 2125W
Concrete slab = 5 x 2.5 = 12.5sq m. Assume 150mm thick, so U = 1/((150/25)*.08) = 2. Also assume undersoil temp = 12degC Heat loss = 2 * 12.5 * (20-12) = 200W


Total loss = 3150 + 743 + 2125 + 200 = 6218W so something in excess of 4kW heating will be needed to maintain a comfortable working temperature.

insulating the roof (R=.12) with 100mm of polyurethane foam (R=1.2 per 25mm) and 18mm of OSB (R = .25) gives a U factor of 1/( .12 + 4.8 + .25) = 0.2 and therefore a loss of 0.2 x 12.5 x (20-0) = 50W, a big improvement.

Similarly the walls, but say 50mm poly and 11mm OSB, U = 1/( .16 + 2.4 +.15) = 0.37, therefore loss .37 x 25 x(20-0) = 185W

Not much you can do about the slab (except put some carpet down :) ), but even now the losses are 185 + 743 + 50 + 200 = 1178W.. a four-fold+ reduction in heating needed...

I'd do something about the door, simply to avoid a temperature gradient inside, it'll feel colder that end!

Caveat... Its really hard to find accurate U and R factors for the actual materials used, so this is at best an approximation, however it shows why insulation is a good thing! Also doesnt account for air circulation and interchange - so you will lose heat through ventilation as well...

[wilfy]

are your worries over the cold workshop to do with myself being too cold or the effective running of a CNC machine in a cold room?

[Jonathan]

are your worries over the cold workshop to do with myself being too cold or the effective running of a CNC machine in a cold room?

if the temerature drops below 5°C condensation may well settle on the machines which will cause them to rust...

[wilfy]

in that case i may consider boxing in the cnc some how with an insulated cover and a small heater to keep the chill off... but the main function of this garage it doesnt need to be kept at room temperature... i've worked in open plan factories with big shutter doors open at both ends, i work outside alot of the day so i consider myself well adjusted.

yes i understand what the problems are with this garage but at the moment in time i'd rather not worry about me being cold and worry more about getting a nice place to do some work in and get some stuff built... this has come a long way from what i had last year, i literally shared an outhouse with the washing machine and had 3 barrels of homebrew on my only worktop in there... so all things considered yes it's not ideal but it's an improvement on what i had.

if i had my own way i'd knock it down and rebuild it and insulate it much better, but that i am afraid is a job for when i have my own house, i prob shouldnt even be doing this but i'll deal with that if i have to