Old cottage renovation, corrugated roof.

eamon11

hello all, old cottage renovation. For anyone with a corrugated roof,can I ask you please how is your roof make up? What size battens did you use and how far spaced? and how did you insulate your roof? I want to put up corrugated sheets too on my cottage and will be insulating from underneath afterwards. thanks a lot, Buky
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Say my name

Get yourself insulated panels if you're going down that route.
It'll deaden any rainfall and do away with any air gaps between the sheeting and insulation, gathering condensation and moisture.

https://www.kingspan.com/irl/en-ie/product-groups/insulated-panel-systems/roof-panel-systems

eamon11

thanks say,

problem is they don't do insulated corrugated panels. In fact, I haven't found anyone who does these. Box profile yes, but the corrugated no.

Say my name

eamon11 wrote: »

thanks say,

problem is they don't do insulated corrugated panels. In fact, I haven't found anyone who does these. Box profile yes, but the corrugated no.

Go into that link and scroll down to the sinusoidal part. Go into that product page and look at the red roof and move down the page to see the dimensions of the corries.

wayoutwest

Hi Eamon - I used 3"x 2" for batons and spaced them so there is a fixing every metre along the length of the corrugated sheet.
20181023_084125.jpg
The corrugated sheeting gives it a traditional look ,as does using roofing nails rather than tex screws.
What is the measurement between your rafters?

eamon11

thanks lads,

Wow Wayoutwest, that house looks really good.
The rafters have not gone up yet. What measurement did you use? And how did you insulate? Plain galvanize sheets painted or PVC coated? Did you have any trouble working the detail for the flues through the roof or what flashing did you use? Would love to see your cottage. Cheers

wayoutwest

Hi eamon - the tin sheets are light enough to put on rafters with, say one metre spacings - this can be seen in old uninsulated sheds BUT if you want to insulate and plasterboard, then you want 400mm centres for rafters.

Tin sheets were plain standard sheets which were cut to the right length with angle grinder (put cut end under ridge, rather than gutter line) + painted. If i did it again, i would use pre-cut, pre-painted sheets - less wastage, less work and cheaper. Make sure you overlap sheets by two corrigations and have overlaps facing away from prevailing wind.

Insulation - PIR on sloping ceiling (make sure you keep 50mm gap between PIR board and roofing membrane to ensure airflow from eavesvents to attic space. Loosefill insulation in the main attic space as normal.

I made the flues come up near the ridge so the homemade lead flashing tucks up under it - not the prettiest job but it works
20181024_093755.jpg
You should really use twin walled flue - safer in the event of chimney fire and less tar build-up on the cooled exterior section.


Best of luck...p.s .you would probably get better advice if u move thread to construction/diy forum.

eamon11

thanks wayoutwest,

any noise issues when it rains?

blue5000

Nice job wayoutwest. Any pics of rafters before you finished the roof?

monseiur

Hi,
A cousin did something similar to ''Wayoutwest'' - he converted a dry walled byre which had a huge loft into a holiday home (he's living in England)
Rafters were 6'' x 2'' spaced at 16'' Battens 3'' x 2'' spaced at 36''
Sheeting - corrugated PVC coated steel with ridge capping to match
Spray foam insulation between rafters this expanded out flush with rafters, vent gaps at soffit.
All inside (external) walls were drylined with insulated plasterboard taped & skimmed, some other partition walls were built with stone to match exterior which gives the house a certain old world charm internally.
The existing floor was replaced with screed over 50mm insulation.

Regarding stainless steel flues thru roof- for fire safety reasons use twin walled flue, there are special flexible flashings available that can be moulded to suit corrugation of roof - Roof N Stop in Dublin stock them.
For block / stone built standard chimney lead flashing as used on slate / tiled roof will do.
M.

eamon11

Hi Monsieur,

I presume he used felt as normal, but can I ask you if he left a 2 inch Gap between insulation and felt? And did he use treated battens? Thanks a lot.

wayoutwest

Blue 5000 - I'm afraid i haven't got any pics of rafters.
Eamon - I use the building as a workshop and usually make a lot of noise making things with stereo turned up loud so I'm not sure/haven't noticed how loud the rain beating on the tin is. Was hoping it would lash down tonight so i could tell you, but its only drizzling lightly atm.
Making your rigid insulation (in sloping part of roof) the thickest you can buy , putting two layers of loose fill in attic and using insulated plasterboard should stop any noise transference. You could go for a 'warm roof' contruction - which, I guess, would give you more accoustic insulation because the PIR boards are on top of the rafters.
20180424_203057.jpg

monseiur

eamon11 wrote: »

Hi Monsieur,

I presume he used felt as normal, but can I ask you if he left a 2 inch Gap between insulation and felt? And did he use treated battens? Thanks a lot.

No felt under sheeting, the sprayed on insulation foam was applied directly on to the sheets, it expanded into gap between rafters & battens etc and out flush with the joists, so the insulation is almost 8'' thick. It's serves a duel purpose of being an insulation for the attic space and stops condensation on inside roof sheet.
Battens were 3'' x 2'' pressure treated

M.

eamon11

thanks a lot Moseiur,
is it not risky having no felt? If any rain water got in it would destroy the insulation and the roof? Was this method approved by a professional? I appreciate your input and help.

monseiur

eamon11 wrote: »

thanks a lot Moseiur,
is it not risky having no felt? If any rain water got in it would destroy the insulation and the roof? Was this method approved by a professional? I appreciate your input and help.

I don't think the method was approved by an engineer, and the felt would definitely be an extra layer of defence, it would also direct any condensation drip towards the gutter.
But thousands of square metres of roofs on shopping centres, factories etc. are covered in foam backed sheeting without felt - it's basically the same principle. Check out Kingspan's insulated roof and wall cladding, I think they're based in Cavan.

m.