New workshop, new roof...

Having recently moved shop I now find myself beneath a corrugated aluminium roof. First order of business was to seal the various gaps and holes to prevent the ingress of rainwater - but I also need to tackle the problem of condensation. I'm sure many readers here will have dealt with such problems before - any handy hints? It's likely that I'll resort to insulating the roof - if only to save heat and cut out the noise of the rain.

Cheers,

Reply to
Stephen Howard
Loading thread data ...

Probably the best solution is to buy a hygrostat (a humidity controlled switch) and connect it to a dehumidifier. Having said that, I haven't done it yet.

Best wishes,

Chris

Reply to
Christopher Tidy

Mine used to have a corrugated glass fibre roof. It was a nightmare in the winter, ice would form on the underside overnight, then a bit of heat in the morning would melt the ice & would literally be rining in the shop. Get it insulated as soon as you can!

Cheers Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Reply to
Tim Leech

..Just avoiding the drips here...

I used expanding foam to seal up a few holes, and I notice this morning that although the roof is completely covered in condensation, none of the spot of foam are wet...even small beads. My concern is that if I insulate the roof without first addressing the condensation problem, I run the risk of simply 'boarding up' the problem. Might grab a bottle of that spray foam insulation and see just how thinly it can be applied and still make a difference.

Regards,

Reply to
Stephen Howard

Stephen,

It is absolutely vital that the insulation you choose does not allow water vapour to pass through it onto the cold metal surface. THis will condense and saturate the insulation and then drip though into your workshop. As you have seen the foam sprayed areas are quite dry and this type ofinsulation will quite likely be the best for your application.

I don't know what the cost would be or how much you have to cover but getting a contractor in and spraying with 2 part polyurethane foam might be worth considering. There is a system that is used to spray the underside of slate roofs which bonds slipped slates. This might do the job and be available in 'domestic' quantities more easily.

Good Luck

Bob

Reply to
Bob Minchin

I'm told the standard practice is a triple layer comprising a ceiling layer, a waterproof membrane and some kind of insulation. The question is whether this is enough to effectively cure the condensation problem on an ali roof. I'm still uncertain as to whether it would be best to seal the insulated roof ( at the ends ) or leave it ventilated.

With 400 sq ft to cover I could be looking at the best part of £500 for a diy foam job...and that's a LOT of beer tokens.

At least ( so far ) I haven't noticed any moisture condensing on the tools..

Regards,

Reply to
Stephen Howard

Or tiled ones. And which, in my experience, is advised against by architects and surveyors as a bodge that makes any subsequent work virtually impossible.

We know this shop has a corrugated roof, but what of the rest of the construction? Is it worth doing properly? Would it be a good idea to bite the bullet, take the bull by the horns, face the inevitable, seize the moment, and fit a real roof, now?

Reply to
Charles Lamont

I built a box under the apex on mine ...this is vented at both ends

The fascia boards have a vent between each rafter ....the whole lot is then insulated with a double layer of acoustic tiles ...that I got from a supermarket that was being revamped. ...FREE

The first layer of acoustic tiles I nailed up to the underside of the rafters...putting a mixture of crumbled acoustic tile and pva mixture up against each tile as cement between each panel.

The second layer was nailed on again (longer nails) but staggering them so the joints didn't line up with the first layer.

The cavity above them is vented from the fascia boards...right up to the box under the apex ..

The fascia board vents are behind the gutters ...so they don't get the howling wind blowing up them

Works really well ...and I noticed a hell of a difference in machine noise now ...everthings so much more quieter.

I heat my place with a paraffin jet engine type thing ...on a thermostat...set at 12 degrees

no condensation ..... well only a tiny bit on the windows when its in the minuses outside.

the secret is ...constant temperature 24/7

walls warm up...machines warm up .;..and there is no cold surface for it to happen on.

if I wasn't to keep it constantly heated like this ...in the winter I would have massive problems if I went and turned that jet engine thing on then.

I am now looking for an old oil fired central heating boiler ....I will have this connected to a car radiator in the roof ...with a fan blowing thru it downwards .,.....advantages would be ...safer ..use the same amount of fuel ...and maybe I could get away with leaving the workshop for a few days unheated ...the space heater thing, don't like all these start ups and close downs ..the nose cone corroded away within the first few weeks...after that I had the thing pointing into a large metal box ...so I could sleep at night...without worrying about the fire risk

Last year I was using a lot of paraffin at first ( about two weeks before I realised) because I was heating too 17 degrees .

I then realised I could get away with just ten degrees ...and raise it to 17 degrees whist I was in there ...without creating a due point .

Once the workshop is up to temp ...it keeps warm and the spaceheater/jet thing only comes on for 7-8 Min's every 1.5 hours ...at normal winter temps

When it's freezing it will come on every 45 Min's for 8-9 Min's

Total cost of heating it from November thru till May at 10 degrees worked out about =A3150 in paraffin. (bulk delivered)...6 months ....83p a day ...and its a 26 x26 workshop with apex roof ....so must have done something right with the insulation.

Not keen on the space heater this year .....tried it, and it works .=2E.but too risky for fire risk and insurers me thinks.

Anyone here running one of those listeroids here ....with a generator set-up.

I could get two bangs for the same buck with one of them.

All the best..mark

Reply to
mark

Along those lines, I believe that Corus (British steel) do pre-foamed roofing panels with about 2" of foam on, We have used them at work in a number of locations and they are very satisfactory. A completely over the top solution is Structural Insulated Panes like wot I used in my shed. They are a bit heavier (up to 100kg for an 8'x4'x6" sheet) but they are pretty strong and don't let the warm out or in.

Mark Rand RTFM

Reply to
Mark Rand

Funny. I was thinking the same thing ;)

A decent roof need not be expensive, but it helps very much to know someone in the trade.

My main workshop has a tiled roof hipped both ends, with about 1000 marley concrete tiles the building is 30 x 12. I think I paid 40p per tile used. Tiled it myself.

The shed at the bottom of the garden is 14 x 12 and has a ridged roof of about 200 sqft +. This is 3/4" Marine ply with a torch on felt. 2 layers. It cost about 150 to buy decent felt and the Father in law torched it on (retired roofer!) These membranes as they like to call them now have about a 20yr life of done properly.

Wayne....

Reply to
Wayne Weedon

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.