Does a Metal garage roof increase the temperature in the summer?

[Hsmith192]

Hi guys,

I’m about to have a roofing quote (again) but is having a metal roof a good idea?


I want it to keep this pesky rain out but not create some sort of sauna room during the summer as I’m woodworking….

Thanks

 

[Terry - Somerset]

I used to have my workshop in a garage with a south facing up and over metal door.

Most sunny days it was like having a 50sq ft radiant panel on full blast for company. Come winter the cold wind whistled past the door. The latter problem will not be quite so obvious with a roof - but the insulation value in cold weather is likely to be close to zero.

Eventually bricked up with double glazed windows.

 

[artie]

Does a Metal garage roof increase the temperature in the summer?​

The answer is yes.

But the question is, how many days in a year will it matter.?

 

[Hsmith192]

Could insulation help to combat the tempreture rise?

As long as it’s not like a greenhouse? It Should be fine?

 

[Jacob]

Yes they get red hot. But it can be designed out if the underside of the metal roof is well ventilated, i.e. big air gap, open at the eaves and vents at the ridge, and a ceiling below is well insulated

 

[stuckinthemud]

Worse than the heat is the drip of condensation from your breath in cool weather; the noise of rain/cats/squirrels/birds can be pretty annoying . Pretty much the worst possible form of single skin roof, but, line it with insulation and a face material and it’s ok

 

[Ollie78]

Hot in summer and drippy with condensation in winter. An insulated sandwich type metal roof is fine, and it can be tolerable if its metal sheet over an osb sheet with a membrane on it. Single skin is a bad plan.

Ollie

 

[okeydokey]

What is the roof made from at the moment? Flat or apex
Would Coroline - corugated bitumen nailed onto osb do the job?

 

[Housey210]

hot, cold, condensation, if not insulated, and noise, many of which all stated. A conundrum!

 

[Hsmith192]

Thanks for your reply everyone. Currently there is an asbestos roof that has had a small leak on it. Sandwiched on its underside is polystyrene- about 20mm?

It does get hot during the summer and it’s not too bad during the winter until temps get below 5 degrees.
It’s an apex roof and I have guttering on one side.

 

[Blackrod]

Does a Metal garage roof increase the temperature in the summer?​

The answer is yes.

But the question is, how many days in a year will it matter.?

Morning, as Jacob said “air gap under tin roof and then insulation with membrane over it and ceiling of OBS.
My workshop it timber fully insulated with a metal roof done in just that way. Never got hotter that 21deg last summer, and stays between 6&10deg in winter.

 

[Hsmith192]

Thanks- really appreciate it.

The roofers have recommended to have insulated panels. Which means the air gap would be after the insulation.

Anyone with some experience surround insulated roofing sheets?

 

[Bristol_Rob]

For such a small garage roof with low pitch you could swap it for an insulated timber deck and cover with high performance felt.

 

[Cobbs]

I've got insulated metal sheets on both my office and workshop - brilliant things. No need for anything else, just fit and forget, cool in summer, warm with no drips in winter and very strong. Bit pricey, but fit and forget. Mine have 50mm insulation and I find that more than adequate. Heavy rain can get a bit noisy, but not a real problem.

 

[Rajiv]

I fitted metal roofing to the garage. I put 6mm ply down first and then a waterproof membrane. Never had a problem with heat when it does get hot and never had a problem in winter. I’ve not noticed any increase in noise—even when it’s raining. If anything it feels less noisy or something is wrong with my hearing

 

[Cobbs]

Rajiv, how did you fix the sheets without driving the nails/screws through the waterproof membrane? Not a criticism, just wondering what purpose the membrane serves...

 

[Rajiv]

I did use screws to fix the metal sheets. My thinking was that if any water got in—it would fall on the membrane and end up in the gutter at the bottom of the roof. Also if condensation did occur then it would drip on to the membrane and not the plywood. It did not treat the plywood with anything. As far as I can see everything seems to be fine. Maybe I’m overthinking it?

 

[Stuart Moffat]

I did use screws to fix the metal sheets. My thinking was that if any water got in—it would fall on the membrane and end up in the gutter at the bottom of the roof. Also if condensation did occur then it would drip on to the membrane and not the plywood. It did not treat the plywood with anything. As far as I can see everything seems to be fine. Maybe I’m overthinking it?

If you use the appropriate fixing screws that have the rubber seal then water won’t run in. They are used on the panels used on many commercial warehouses etc. My 20m x5m workshop stays dry and temperate year round.

 

[Rajiv]

If you use the appropriate fixing screws that have the rubber seal then water won’t run in. They are used on the panels used on many commercial warehouses etc. My 20m x5m workshop stays dry and temperate year round.

Yes that’s what I used.

 

[Cobbs]

My point was more that the membrane would cease to be waterproof once it had screws or nails driven through it and therefore be redundant...