UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > General Vintage Technology Discussions

Notices

General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc.

Closed Thread
 
Thread Tools
Old 11th Jan 2022, 10:10 pm   #1
JoshWard
Octode
 
JoshWard's Avatar
 
Join Date: Dec 2005
Location: Near Stowmarket, Suffolk, UK.
Posts: 1,962
Default Insulating workshop roof- advice sought

Hi all,
Hopefully this is the right section for this. I see I'm not the first to ask for workshop construction advice in this section so hopefully this is allowed. I have tried Googling but conflicting answers have left me unsure, and I know there will be sound advice here!
I have recently moved into a new workshop. I have insulated and boarded out the walls but didn't touch the roof. Now we are in winter I am rather regretting that! I run a large tube heater and a dehumidifier 24/7 to keep it dry and it seems to work. I haven't seen the temperature drop below 10°C in there yet, but I am sure insulating the roof will improve that and reduce my energy use.

When I insulated the walls I went through the whole process- a breathable membrance spaced back from the external walls (which are made of timber), followed by PIR board, then a vapour barrier and topped with plywood.

My question is do I need to do all this to insulate the roof? I understand that damp might get through the timber walls but the outside of the roof is EPDM sheet so there shouldn't be any damp getting in there. Can I simply put up a plasterboard or similar ceiling and stuff rockwool or similar between the plasterboard and the roofing boards?
I have marked out in red on the attached picture where I hope to fit the ceiling. I was hoping to then insulate between this and the roof 'planks'.

Advice gratefully sought!

Josh
Attached Thumbnails
Click image for larger version

Name:	IMG_20220111_191939a.jpg
Views:	310
Size:	94.3 KB
ID:	249545  
JoshWard is offline  
Old 11th Jan 2022, 10:20 pm   #2
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
Default Re: Insulating workshop roof- advice sought

I'd suggest getting some Celotex/Kingspan, cutting it to fit and then gluing it to the spaces between the rafters using something like PinkGrip, dot-and-dab style.

Then squirty-can-foam round the edges and finally panel-over with ply fixed to the rafters.


Kingspan/Celotex is already foil-lined on both sides so it is its own vapour-barrier.

You can often get 'damaged' sheets of Kingspan/Celotex at bargain prices from builders-merchants; since you'll be cutting it down it doean't really matter if there's a broken-away corner or something because you'llbe cutting ot iff anyway.
__________________
I'm the Operator of my Pocket Calculator. -Kraftwerk.
G6Tanuki is offline  
Old 11th Jan 2022, 11:30 pm   #3
Lloyd 1985
Nonode
 
Lloyd 1985's Avatar
 
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 2,814
Default Re: Insulating workshop roof- advice sought

I used foil backed foam insulation in my workshop, mine was branded ‘Recticel’ which I think was a Jewson’s own brand version of Kingspan / Celotex. It’s brilliant stuff, keeps the warmth in during the winter, and also keeps it out during the summer up to a point! I think it was about £16 for an 8ft by 4 ft sheet back in 2016, and I went for the 50mm thick, they had 25mm and 100mm too.

Regards
Lloyd
Lloyd 1985 is offline  
Old 12th Jan 2022, 12:30 am   #4
Silicon
Nonode
 
Join Date: Jun 2007
Location: Coulsdon, London, UK.
Posts: 2,152
Default Re: Insulating workshop roof- advice sought

I would assume that the aluminium foil on the insulation would cut out the radio waves and spoil the reception inside the workshop.
Silicon is offline  
Old 12th Jan 2022, 12:38 am   #5
unitelex
Hexode
 
Join Date: May 2005
Location: Greater Manchester, UK.
Posts: 492
Default Re: Insulating workshop roof- advice sought

I'd also recommend Kingspan/Celotex, works brilliantly.
Ideally 50mm thick, but even 25mm will make a big difference.

You will need to be careful that rising warm air does not get trapped between the insulation board and the timber, as the latter will be colder and will get condensation.
A perfect membrane would work for this but even small gaps will lead to problems. You can get dedicated foil tape to join between your insulation boards which does a good job of sealing to maintain the membrane.

If your membrane is not perfect then best to arrange a small gap between the insulation board and your timber and arrange breather vents from the gap/cavity to the outside to allow any warm moist air to escape.

Chris
unitelex is offline  
Old 12th Jan 2022, 7:47 am   #6
JoshWard
Octode
 
JoshWard's Avatar
 
Join Date: Dec 2005
Location: Near Stowmarket, Suffolk, UK.
Posts: 1,962
Default Re: Insulating workshop roof- advice sought

Thanks folks. I used Celotex for doing the walls and I have certainly been pleased with it there. I only wish I had kept the offcuts from that! I sealed all the joints there with foil tape and then fitted a plastic vapour barrier over the top so I can do that again with the ceiling although it sounds like there may not be any need for the plastic barrier?
Just to confirm, it sounds as though I don't need to have an air gap between the timber of the roof and the insulation?
JoshWard is offline  
Old 12th Jan 2022, 10:43 am   #7
David G4EBT
Dekatron
 
David G4EBT's Avatar
 
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,738
Default Re: Insulating workshop roof- advice sought

Your workshop looks excellent Josh - well done on that.

The well-made 16minute video at the link below might be of interest as it covers aspect of wall and roof insulation of timber outbuildings, in this instance, a 'Home Office'. The point at which roof insulation is covered starts at 7.53 mins in. It's part 15 of the DIY building, which was vert well researched and competently built:

https://www.youtube.com/watch?v=C-eVlYsZ3iQ

You'll note the comment that 35% of heat is lost through walls, 15% through the floor, and 25% through the roof. The rest is lost through windows, doors and air leaks. When I built my modestly sized 8' x 6' workshop, I insulated the walls with rockwool and double glazed the windows. I would have liked to have insulated the roof with Kingspan, but it was prohibitively expensive and I didn't feel that for the time I'd spend in the workshop in winter months that it would be cost effective. That said, I built it 20 years ago, so no doubt by now, it would have paid for itself.

The workshop in the one of the right - the left one is the garden shed I built.

I used Wickes felt roof shingles on the roofs, (with a felt underlay), which are still good as new and far preferable to the more usual mineral felt.

Hope that's of interest.
Attached Thumbnails
Click image for larger version

Name:	Finished - end view.jpg
Views:	167
Size:	95.9 KB
ID:	249554  
__________________
David.
BVWS Member.
G-QRP Club member 1339.
David G4EBT is online now  
Old 12th Jan 2022, 11:45 am   #8
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
Default Re: Insulating workshop roof- advice sought

Celotex/Kingspan etc, this shed is in my garden, radio reception's no problem in there.

Lawrence.
Attached Thumbnails
Click image for larger version

Name:	PB190001.jpg
Views:	142
Size:	57.5 KB
ID:	249561  
ms660 is offline  
Old 12th Jan 2022, 11:50 am   #9
David Simpson
Nonode
 
Join Date: Mar 2008
Location: Aberdeen, UK.
Posts: 2,839
Default Re: Insulating workshop roof- advice sought

Firstly Josh - what a great well-built workshop. There is nothing I can add to other folk's comments regarding insulation & f/b plasterboard. Guess you'll just need a modest heat source, and a bit of ventilation at either end of the roof apex. Likewise a vent low down - one of those 225mm x 150 mm plastic or anodised aluminium jobbies.
David's two sheds also set a high example of construction.

Regards, David
David Simpson is offline  
Old 12th Jan 2022, 12:51 pm   #10
kellys_eye
Octode
 
Join Date: Jan 2014
Location: Oban, Scotland, UK.
Posts: 1,118
Default Re: Insulating workshop roof- advice sought

Quote:
Originally Posted by Silicon View Post
I would assume that the aluminium foil on the insulation would cut out the radio waves and spoil the reception inside the workshop.
I came across a LOT of cheap foil-backed, bubble-wrap type of insulation many years ago and fully lined a workshop (behind internal OSB wall panels). It worked extremely well and keeps the place cool in summer, warm in winter.....

....only to be perplexed some years later at the poor reception when starting on radio reception hobbies and forgetting what I'd lined the place with!

Spent HOURS wondering why my new SDR system wouldn't pick up anything but noise! Then Mrs k_e opened the door to ask if I wanted a cuppa........ Signals! I'd even lined the DOOR!
kellys_eye is offline  
Old 12th Jan 2022, 1:29 pm   #11
mhennessy
Dekatron
 
Join Date: Jul 2007
Location: Evesham, Worcestershire, UK.
Posts: 4,241
Default Re: Insulating workshop roof- advice sought

Just a caution on Ali Dymock's (excellent) garden room build: he uses the warm roof scheme.

That means his insulation is above the timber, but below the EPDM roof. So all the roof timbers are inside the thermal envelope, and won't get cold enough for condensation to form.

However, you can't do that - you already have the rubber in place, so you have a cold roof (but see below).

This means that - in theory, at least - you need a 50mm void above the insulation, and that void must be ventilated to avoid condensation in that cold space.

In practice, you might not need to do that, given that this is a low-occupancy room, with (presumably) no-one sleeping out there, no bathroom or kitchen, etc.

If you look up "Oakwood Garden Rooms" on YouTube, you'll see that they use a "hybrid" system for their roofs. This has come in for a lot of criticism in the comments, but they do have a report from an expert that suggests their system is OK because the rooms are low-occupancy. Note that this report was submitted voluntarily by a viewer who was frustrated with the YouTube comments, so it's probably pretty impartial.

Anything between the two extremes of "cold roof" and "warm roof" is defined as "hybrid", and in theory, you are supposed to submit calculations to justify any hybrid builds. Of course, this is just a shed, so you've only got yourself to satisfy!

Oakwood's hybrid system is to simply to put the PIR insulation in contact with the underside of the timber that the EPDM is attached to - there is no ventilation. They do install a vapour barrier on the warm side of the insulation, but inevitably this gets punctured by electrical fixtures. Their report suggests that this isn't the end of the world though - because - guess what - it's a low-occupancy room!

In fairness, most moisture in a building does come from us and our activities...

Ali Dymock did re-visit this subject. Cold roofs are popular with shed builders because of the 2.5m height restriction - he got planning permission for his build, so had more height to play with - but he went into more detail for the benefit of those who are working within the "permitted development" limits - well worth a look: https://www.youtube.com/watch?v=sw5WsdPtChc

He does suggest that the nominal 50mm air space between insulation and roofing deck could probably be reduced in a typical shed/garden room, given the low occupancy, and I'd tend to agree. Likewise, Oakwood have shown pictures of one of their builds that is several years old, and there's no sign of condensation or similar. So based on that, I'd say the easiest solution for you might be to put some PIR in the roof with no gap between the insulation and the roof boards. Include a vapour barrier on the warm side, then plasterboard. Aim for at least 50mm PIR if you can - though it's not cheap at the moment. Insulated plasterboard might be worth considering in addition to whatever PIR you can get in the roof.

Sadly, I can't see how you could do a proper cold roof without compromising the strength of the structure. With the benefit of hindsight, the best solution would have been to go to a warm roof, with insulation outside. Given that EPDM isn't all that expensive, I'd even consider putting insulation and new rubber on top of your existing rubber roof. That's been done at work (we have a lot of timber buildings here), and it does work well - although there are aesthetic elements to get right (and you might run into the 2.5m limit?). Doing that retains the internal head height, plus the view of the timbers - which does look rather nice IMHO

If/when I finally get around to building mine, I plan to go "cold roof", using 90mm PIR with 145mm timbers. As it's a flat roof build, these timbers will be tapered down to about 110mm to give the slope, so my air gap between insulation and the roof deck will fall to 25-30mm at one side, but I think that'll be fine. Knowing how much time I'll spend out there - especially with "flexible working" now - I'm not quite confident enough to go for the hybrid roof that Oakwood and others use, but that might well change when it finally happens!

Mark
mhennessy is offline  
Old 12th Jan 2022, 2:10 pm   #12
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Insulating workshop roof- advice sought

I would want first of all, a de humidifier.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 12th Jan 2022, 6:48 pm   #13
agardiner
Octode
 
agardiner's Avatar
 
Join Date: Sep 2020
Location: Thetford, Norfolk, UK.
Posts: 1,731
Default Re: Insulating workshop roof- advice sought

I would love a workshop like that!
agardiner is offline  
Old 12th Jan 2022, 9:19 pm   #14
trsomian
Hexode
 
Join Date: Oct 2010
Location: Box End, Beds. UK.
Posts: 271
Default Re: Insulating workshop roof- advice sought

May I suggest that before you put whatever insulation you choose in that roof you give the timber another coat of a good preservative, because it will be difficult to get at later, and it won't breath as easily as it does now. I commendably tidy shed I must say
trsomian is offline  
Old 12th Jan 2022, 10:23 pm   #15
Nymrod121
Nonode
 
Nymrod121's Avatar
 
Join Date: Apr 2012
Location: Worcestershire, UK.
Posts: 2,039
Default Re: Insulating workshop roof- advice sought

Quote:
Originally Posted by trsomian View Post
May I suggest that before you put whatever insulation you choose in that roof you give the timber another coat of a good preservative, because it will be difficult to get at later, and it won't breath as easily as it does now. I commendably tidy shed I must say
I used 'Barrettine' on mine; two coats, 1 week apart, inside & out. The wood drinks it ... my m.o. was to use a paint tray & small foam roller (but watch the drips/'spin-off' spray) and a 1" brush for the fiddly bits.
Best wishes
Guy
__________________
"What a depressingly stupid machine." [Marvin: HHGTTG]
Nymrod121 is offline  
Old 12th Jan 2022, 11:06 pm   #16
Uncle Bulgaria
Nonode
 
Uncle Bulgaria's Avatar
 
Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,315
Default Re: Insulating workshop roof- advice sought

I prefer breathable construction. No chance of interstitial condensation and no off-gassing from petro-chemical insulations or other health hazards. I'm building a house using an untreated timber frame with wood fibre insulation. Woodwool board on the outside and OSB on the inside face of the stud walls.

I gather you've got a rubber coating on top of the boards shown in the photograph. Evaporation to the outside is thus rather difficult, but if you're not inside generating large amounts of water vapour all the time, then I would posit you'd be fine with wood fibre in your rafters with a woodwool board beneath (Celenit, Savolit, Heraklith etc.) This is a common ceiling finish for acoustic purposes, and I think it's quite attractive left as it is.

The main problem with foam insulations apart from their environmental footprint is their inability to hold and release water, making buffering variable humidity impossible. You haven't got cooking or bathing facilities in your shed, so you won't be making a lot of wetness.

Some further information in quite an engaging style is available here: https://www.heritage-house.org/stuff...thability.html
Uncle Bulgaria is offline  
Old 13th Jan 2022, 12:47 am   #17
wireman
Heptode
 
Join Date: Feb 2021
Location: Edinburgh, Scotland, UK.
Posts: 528
Default Re: Insulating workshop roof- advice sought

I was looking into this topic a year ago for my shed with I think 50mm framing. This reference looked good...

https://gilliesandmackay.com/how-to-insulate-a-shed/

Different thicknesses of insulation had varying effects...

Thickness (mm) Thermal Resistance (m2-K/W)
20 0.85
25 1.05
30 1.30
40 1.70
50 2.15

Some advice was to have a moisture barrier on the inside, from the insulation itself along with tape. Have a gap at the back of the insulation. Huge variation in advice on what gap is needed, ranging from 2cm to 2".

I really was not sure what advice to follow. Beyond cold in the winter one probelm I have is the heat radiated from the roof in the summer, the maximum temperature so far in the shed was 37.8C.

Nothing will be perfect, the door is not exactly airtight but any improvement would be good if it was not too expensive to do. I also have airflow within the shed from two vents (one low at one end and one high at the other).
wireman is offline  
Old 13th Jan 2022, 8:33 am   #18
JoshWard
Octode
 
JoshWard's Avatar
 
Join Date: Dec 2005
Location: Near Stowmarket, Suffolk, UK.
Posts: 1,962
Default Re: Insulating workshop roof- advice sought

Thanks all, this is really helpful. I run a dehumidifier in there 24/7 so any moisture produced from my minimal presence (no more than a couple of hours every few days at this time of year) should soon be collected by that. There has been no condensation on the single glazed windows yet this winter, so it must be nice and dry in there. I will be making some secondary glazing and will probably do this next before starting on the roof.

The 'warm roof' idea sounds interesting but alas would push me over 2.5m in height.

Sadly, if I allow for a cavity (and there is space for one) there's no way I will be able to ventilate it, so I wonder if it would be worse to have an unventilated cavity than to go down the 'cold roof' route with insulation touching the timbers? I can do either 70mm board touching the roof or 50mm board with a 20mm air gap but no external ventilation.

Thank you for the kind coments about the workshop. I can't take credit for the construction, it was an 'off the shelf' building from a local company. I have to say I am impressed with it. It's certainly very well built. I have spent the last 7 seven years working in a lean to at the back of the house. It was leaky, built straight onto the old concrete yard at ground level, downpipes and gullies inside it etc. The new one will have cost me a fair bit by the time I have finished paying for it (!) but it has been worth every penny. The photo was taken back in March when the shell was built. That was just the start as it took until late summer to insulate it all, carpet it, fit electrics, shelving, workbench etc!

I do have one more question. Ventilating cavities has been mentioned. When I did the wall insulation (see attached crude MS Paint drawing for how I did it!) I did not add any external vents. Do the cavities behind each insulation board (betwen each batten) all need ventilating seperately? If I ventilate only a couple will the air from outside actually be able to get to where it needs to be? I'm not sure I fancy having a line of portholes all the way round!

I like the comment R.E. cooking and bathing facilities. It's tempting to add them!
Josh
Attached Thumbnails
Click image for larger version

Name:	IMG_20210328_175454.jpg
Views:	110
Size:	115.7 KB
ID:	249612   Click image for larger version

Name:	Insulation.jpg
Views:	74
Size:	17.1 KB
ID:	249613  
JoshWard is offline  
Old 13th Jan 2022, 11:33 am   #19
Lloyd 1985
Nonode
 
Lloyd 1985's Avatar
 
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 2,814
Default Re: Insulating workshop roof- advice sought

I didn’t leave a air gap between the insulation and the roof in my workshop, I did leave a gap between the plasterboard ceiling and the insulation (oops, did it the wrong way round!!) and so far I’ve not had any problems with condensation that I know of, I did put a bathroom fan in the ceiling vented to outside, mostly just to clear out solder fumes. I don’t run a dehumidifier in there, but I do have double glazing, I got a really good deal on a new UPVC door and window from a local company.

One thing I did fit in my workshop is a small hand wash basin! It’s proven very useful, saves having to make a trip to the house just to wash my hands after opening up something grubby!

Regards
Lloyd
Lloyd 1985 is offline  
Old 13th Jan 2022, 11:56 am   #20
David Simpson
Nonode
 
Join Date: Mar 2008
Location: Aberdeen, UK.
Posts: 2,839
Default Re: Insulating workshop roof- advice sought

Once again Josh, your latest picture shows a lovely built shed. Certainly a super size which many of us would be jealouse of.
Raised off the ground level on a concrete base - just the ticket. One wee recommendation, as an addition to the excellent guttering & double down-pipes - maybe dig soakpits a meter or so away from the concrete corners & maybe remove the grass & topsoil from next to the concrete slab & replace with 450 x 450mm paving slabs - when time & money permit in the future.

Regards, David
David Simpson is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 3:33 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.