Cold Flat Roof Ventilation Corrected

[@gwilko6452]

99% of the jobs we do are warmroof installations thankfully. Cold roofs ar few and far beetween. Just completed one recently due to its L shape design plus a roof lantern we couldn't vent the whole of the roof. Thankfully he hasnt insulated or plasterboard as of yet. I shall be forwarding this on to my customer. Thanks

[@SteveRoofer]

Thanks

[@beadymel]

I wish we'd known this before my son had his roof done! Great video, very informative! Thanks

[@SteveRoofer]

Glad it was helpful!

[@MikeNewland]

District Surveyor in the early 1970s said put inch holes through middle of joists on flat roofs to allow ventilation. At the time insulation tended to be two inches so did not block the holes if placed at the bottom over plasterboard. Often people put it at the top still no problem. I think what has happened since then is people sealing up their rooms and avoiding ventilation so more moisture to get into the joist space.

[@Pwak54N]

Hi Steve, how do you add lighting to an area like this without breaking the vapour barrier?

[@ooslum]

Great video explaining and it's always clearer with someone's mistakes. Any chance of more explanation on the very last bit where the new meets the existing roof and the best way to maintain the ventilation of both.

[@HampsteadBuildersLt]

Yes, you could be compounding the problem. If you don't do it totally correctly, its going to be a problem. So you need to vent and you need to have a AVCL. If however if you don't do it correctly, then I would have suggested packing between joists with Rockwool I've seen that work in the past to you have to ask yourself why isn't it working now? are you sure the roof isn't leaking somewhere? Is the moisture content int he rooms below to high ?

[@zaz7675]

Fantastic run down Steve! I’ve been glued to your videos and detailed analysis for a while. It’s a great resource :) your experience is top class 🙌🏻 I’m designing my garden room build at the moment. I’m in Scotland. Super keen on doing the warm roof system. One element I’m trying to consider is how to encourage the flow of air around the perimeter of the roof without making use of a soffit. I’ve built the timber frame and layering of warm roof in 3d and I want to make sure I have everything modelled up before breaking ground in early spring.

[@SteveRoofer]

Send over details [e-mail]

[@Fightssss]

Steve great videos Only thing I can't work out is When you screw up your plaster boards are you're screw piercing the vapour barrier ???

[@blackjono2000]

Good question

[@SocialistChampagne]

At 5:53, did those donuts put the ply on top of the 1f felt?

[@Copeinked]

The ultra top looks great over the flex. Really nice job, frayed seams and full consolidation of the reinforcement!

[@SteveRoofer]

Yes even when he added the mushroom vents he did a nice job

[@liamhuson6746]

How did the spotlights be installed if the vapour barrier can not be pierced and do you have to make a bigger hole In the insulation?

[@dascorp1]

Steve could you make a video about abutment and airtightness layer continuity of new (say extension) warm roof to the existing vented cold pitched roof. What I found confusing is the transition of a vapour barrier or airtight membrane which is on top of the deck below PIR insulation into the airtight layer which is below roof truss bungalow and above ceiling service cavity. Two environments shall not mix - the vented attic is full of vapour rich and cold, but space between joist of the new flat roof is below is vapour rich and warm.

[@tipthebalance]

Ooooh so many questions! We have a flat roof dorma crofloft and pulled the ceiling down as it was falling in. Turns out the roofers/previous owners had packed the gap with rockwool, so condensation meant it had turned black and was soaking wet. I’m trying to fix from below atm (I’m a woman with no spare money to speak of right now!) so was planning to put 50mm kingspan between the rafters, a breathable membrane, then plasterboard, leaving a 20mm ventilation gap at the top. I don’t have much depth to play with and There is no ventilation from the fascia boards. Am I compounding the problem by doing this? Cheers Steve.

[@artivision1]

Sooooo.. i got trown into this becouse someone i know followed your way of working.. after i tryed to explain him why it was a bad way of working he showed me your video... i had put my opinion of this aside and went to my big circle of "smart people" (being a group of architects, salesmen and fellow roofers) they all reacted the same as i had in my mind. 1. The airflow will CREATE moisture AND lowers the vallue of the isolation. 2. The correctly installed vapor barier solves the problem.. if u would have punctures, tape it. 3. The reason the guy had droplets/condense was becouse he had the building isolated and warm on a cold day and had no vaporbarier and no plastering yet. So you solved the problem by installing the vaporbarier but then allowed moisture air in again by creating airflow. And as most people use rockwool etc between the beams it lowers the isolation value by allot. This method is way outdated and good when isolation was not a big deal yet and people did not use good quality vaporbarier yet.. people have gotten smarter then this. Just my opinion after a long and wide discution and research about this. Its ok if you do not share my opinion, but if you insist my reasoning is still wrong, please do point out where i go wrong.

[@SteveRoofer]

This is excellent as you are right in so many ways. Everything I put forwards on my videos is info that from my understanding is the latest information from the British building regulations. Personly I don't always agree with it, but we have to follow protocol or we can get sued. I understand that SIGA is basically saying the same as you and they want to use open-cell insulation such as rockwood, but here in the UK, we are mainly using closed-cell insulation (PIR), and that makes a lot of difference you have to ventilate above.

[@davidbarnett8002]

Downlights need a breath space round them i always do a 25mm cross batten on top of furrings on a cold roof

[@Solidsnake0208]

I always ask myself what these vapour barriers are actually doing when you're looking at atleast 24 holes through it for every sheet of plasterboard you fix. When the insulation is foil backed and the joints are taped, isn't that essentially a vapour barrier? I'd say the removal of the recessed downlights will be the biggest difference here.

[@SteveRoofer]

There used to be an article are used to refer to that was called when is a vapour barrier not a vapour barrier and the answer is when there is something else actions as a vapour barrier in the wrong place. So having a paper barrier is a good idea, but having too many layers that could activate Barrys is not so clever.

[@scottparden-bell5454]

Hi Steve , with the new green vapour barrier he has put on his ceiling , where and how will he penatrate that for his lights ? Will this cause a problem

[@SteveRoofer]

Ill show that in my next video

[@grasielasantos8949]

Hi Steve, I have a cold roof and I do not have any sweet yet, as far as I am concerned, but we have no ventialtion wahtsoever on our roof. we are do add ventilation in the front of the extension( the roof) and we are hoping it sort the problem. is that something you would advise? does it need to have ventialtion both sides? front and back?

[@SteveRoofer]

Yes absolutely you need to add as much ventilation as you can and make sure it's through ventilation so that it can flow from the top to the bottom or from side to side. You only have one vent on one side, the air can't push through

[@RowRow78]

Maybe a silly question, but how does the plasterer put his plaster boards onto the vapour barrier? My guy has just drilled through it into the beams - surely making it pointless as it now has loads of holes in it?!

[@Sileesosij]

Great question, was just wondering this myself.....seems the only way to have a perfect vapour Barrier is not to have any lights or plasterboard!

[@arbit3r]

Screws and nails dont leave holes unless you remove them.

[@igloodesigners]

Hi Steve thanks for these videos Im going to start some insulation in my loft so it would be a cold roof just wondered if you had a video on this was going to use some kingspan inside the rafters with a 50mm gap between the felt and then some insulated plasterboard but looking at this vapour barrier looks good.

[@raykhan6416]

Amazing work thanks

[@myatix1]

Thanks for sharing Steve! Great channel! Any tip on ventilation between an adjoining pitched roof and a flat roof? Would love to hear what you have to say! :)

[@gauravsingh84]

Hi Steve, Great video! I learnt about all the things wrong with my sweating roof. I will have to tear down the plasterboard ceiling from inside and do a very similar job to this person. You mention at the end that the person who did this has since checked on the roof and it is dry. How is it possible to check the status of the roof after creating the vapor barrier? The only access point I can think of is via the mushroom vents at the top.

[@SteveRoofer]

Yes thats one way or we cut into the roof but thats costly intrusive

[@OidHunter]

Poke a semi-rigid endoscopic WiFi camera through the vents

[@kylecroft5807]

Question Steve, what way do you go about fitting lights with the vapour barrier?

[@SteveRoofer]

If you want to put a Spotlight into a cold roof you have to think of the following first it's going to sit in insolation that is sealed all the way round so there will be no movement and no movement of heat away from the light fitting so the light fitting will need to be probably LED because they admit very little heat the problem here is that LED lights normally are low voltage so you have a transformer that gives off heat. If you place the transformer in the installation it will overheat any few places above the insolation in the cold vented space above you can't get to it for maintenance. So the traditional type of spotlight is extremely difficult to successfully fit in a Cold flat roof. We find most people cut through the vapour barrier if there is one through the insolation and let the heat from the light dissipate into the void above the vented void above the cold vented void above. This then allows the warm moist air from below to rise up into the vented space above the installation and when conditions allow this moist air condenses onto the back of the roof decking. The installation is now 90% useless as the hot air is bypassing the installation and getting out of the building. The vapour barrier may as well not be there as more moisture is moving with the air then what the vapour barrier would have held back in the first place.

[@kylecroft5807]

Steve Roofer warm roof is the better then, cuts out those problems. What’s the situation on a lean to roof? Also thanks for the reply

[@allcitysparks9685]

@@SteveRoofer Just thought I'd mention that these days, most (if not nearly all new downlight fittings) don't use transformers any more. They are all mains voltage, but can still be LED (either LED bulbs or fully integrated LED fittings). Great videos by the way!

[@Craigo5000]

@@SteveRoofer You can now buy mains voltage LED lights without the need for a transformer.

[@davidpark905]

How would you insulate the 2nd floor ceiling and attic in a cape cod home?

[@garystratton8731]

Hi Steve are you saying that you cannot safely fit downlights in a cold roof. I ask because i currently have a flat roof and want to fit downlights around the perimeter? So therefore, if you have a cold roof are you advising you cannot have downlights at all? What about with a warm roof system how does this work with downlights?

[@EvanAndrews7]

Would cross batterning on top of the firings work to let air flow throughout the whole roof?

[@SteveRoofer]

Yes, cross battening is definitely a good solution

[@lawrencewhite4362]

Hi Steve, Loving this vid! Really helpful. I have a question - I'm making a cold roof for our garden room. 5x2 rafters. 120mm Celotex board would completely fill the depth between rafters. I'm going to drill holes (like in the vid) to help air move... Should I get only 100mm Celotex, so air isn't blocked by that final 20mm of insulation board..??? Would appreciate your help. All best wishes and thanks, Lawrence

[@eddieduff9740]

If you can 100% air seal the entire roof and still allow for electrical etc then you don’t need an air gap. If there’s the potential for air leakage then an air gap is required

[@Ghost_Rider_786]

Hi Steve I have a builder in at the moment, he's put the joists in and he's put the roof on, and he's told me he is going to fill the joists with a wool type insulation, he's made no mention of air flow, or vents or vapour barriers. Can you give me some advice on what he should be doing please ?

[@brocklanders1984]

Great video Steve! Did he completely do away with the spotlights then?

[@SteveRoofer]

Yes howver you can have spotlight if you don't have deep ones and they don't make lots of heet as they sit in the insulation and the heet cant dissipate

[@GMLondon]

@@SteveRoofer thanks Steve- how do you do that without breaking the vapour barrier or is it okay to make a small cut in it? Thanks mate

[@grahams6690]

Hi Steve, great video, who is the manufacturer of the mushroom vents please.🙂 I need some for grp system.

[@SteveRoofer]

Extra Aqua Flat Roofing Vents about £11 per vent

[@tonyduignan9720]

Hi Steve , in that video how did he fit spot lights back up now there's a vapour barrier in the way ?

[@Craigo5000]

I'd love to know how too. Its all well and good saying don't cut the insulation and vapour barrier over it but how do you run a light in the exact same place using the existing wiring? Surely now it can all breath it won't matter too much because the warm moist air can travel through all the holes and not condensate. Granted, it's not going to be 100% thermally efficient, but he gets his lights and now has no moisture trap. I'm in the same predicament with a cold flat roof with only soffit venting on the face. It needs venting on both sides and crossflow drilling adding. Mine is also underdrawn with more insulation under the rafters aswell as in the rafters so this will stop thermal bridging but it's impossible to not cut my insulation for the spot lights.

[@Craigo5000]

I worked it out if anyone wants to know. I have no ridge airflow and only had a dorma face continuous vent strip so I added continuous vent strips in the dormer cheeks and drilled 32mm holes through and down every firring above the joists. I ended up removing all the insulation and amending the wiring runs to sit above the 100mm PIR requirement for my rafters (inside the 50mm airflow gap). Then at the spot lights, ran the wire down the side of the rafter and into a square cutout for a product called 'Thermahood' which is a sealed cover to prevent heat loss and air exchanging between the warm and cold side. I then also back filled the Thermahood with expanding foam which is friction fit inside the 100mm PIR and then added a 30mm PIR 'cap' ontop with the expanding foam helping to seal this all together. Finally, I dropped a plumb line, marked a big red X on the floor and then underdrew it all with another layer of 30mm PIR, taped all the seams and then added a VCB. Once plasterboarded and skimmed, I then used the plumb line to find the exact centre of the wire within the middle of the Thermahood and drill my 70mm hole to fit the LED spotlight and the hood can house any excess cable etc. The whole lot is airtight and thermally efficient. I had 21 spot lights to apply this method! If you want, I'll make a video on how I did this. It seems no one has ever used thermal hoods for spot lights and this seems a massive challenge for most builders to understand.

[@bigkieth23]

@@Craigo5000 yes please, it would be good help

[@SteveRoofer]

No, as I don't do cold roofs but all I can say is make sure it's fitted correctly taped at all joints and sealed to the walls so its totally air tight don't cut spotlights into it

[@brianshires2720]

Hi Steve, I’ve got a flat roof I could do with a bit of advice on, could I send you some photos of what I’m planning and what’s there now? Your videos are really great

[@SteveRoofer]

Yes please send them though [e-mail]

[@Joey-hu3ed]

Hi, could you help, give advice on my build please. I’m changing my shed into a summer house really need some advice regarding air flow ect to stop mold and damp occurring. Please help

[@thomasdavid6730]

Hi Steve, i'm in Canada ( zone 6) and i have a 2x8 cold roof with EPDM , 3/4 plywood sheathing, 2" vent space , 3/4 inch EPS foam baffles ( sealed to joists) , 5 1/2 inch FG insulation, and 2.13 inches (R-10) of EPS foam sealed at all joints with a laminate to stop thermal bridging. My questions are is the 2.13 foam acceptable as an air and moisture barrier ? and should the 3/4 foam be sealed to the joists,in case of moisture getting by the 2.13 foam .Thank You for the videos and your time

[@SteveRoofer]

No you need a proper VCL now called an AVCL air and vapour control layer if zone 6 is a cold zone then it goes under the insulation

[@DeanW-1990]

So how did he install his spot lights can’t not just have spotlights ?

[@briangriggs7651]

Hi im doing a cold roof construction and they've said to use 9 inch timbers with 8 inch cellotex and foil back plasrerboard as a vapour barrier do you feel the airspace of 1 inch is adequate enough and the foilback plasterboard is enough thankyou .for your time and your help in this matter would b most appreciated .

[@SteveRoofer]

Building regs want 50mm air gap minimom on a cold roof. you need to install a proper AVCL air vapour control layer to the underside

[@briangriggs7651]

@@SteveRoofer thanks for such a speedy reply Steve i thought it was 50 mm myself would you suggest counter batterning then steve .thanks mate .

[@SteveRoofer]

yes but make sure you do a good avcl

[@briangriggs7651]

@@SteveRoofer thanks Steve can you recomend a good vcl as there are so many please .thankyou

[@douglasthompson2740]

I am wondering how you can deal with condensation in a roof/deck which is blocked between the joists/rafters but open to the ambient air. The problem comes from the fact it houses a mini-split which keeps the inside air (although it has large air opening below and above the door plus the aforementioned open joist bays at the plates) about five degrees F less than outside air (ninety nine percent heating during the year-only three or four days when the a/c is needed). Getting mold growing on the underside of the roof deck which is 1 1/4" plywood with a thick fiberglass coating on the walking surface. I was surprised as I had thought the air flow and circulation would have kept any condensation at bay. All inside studs and joists are uncovered by the way. When the mini is on it blows a real blast of air which confuses me even more as I would regard that as forced ventilation in open spaces with plenty of free air to draw from. Moisture is a fact of life here in SE Alaska in a temperate rain forest with high humidity, frequent high winds and a temperature range of 10+ F to 80 F very infrequently mostly staying between thirty and sixty year round. Walls are doing well, just the ceiling (underside of the deck) is showing mold after a year of use. Can't see where a vapor barrier would help making dead air pockets in an unheated roof structure. Seems to be more pronounced in the 25-40 degree temperature range.

[@SteveRoofer]

Please email me over photos and I will see f I can help [e-mail]

[@TheElectricbluey]

Hey Steve thanks for all the great videos. Just wondering if you can use an insulated plasterboard for the ceiling on a warm roof? I was going to do this on my extension.

[@SteveRoofer]

No you can't because that would not be a warm roof a warm roof means that the lower decking is warm the lower decking on a warm roof is actually internal you don't need a ceiling all your joists are internal the lower decking is internal the vapour barrier is on top of the lower decking everything above that vapour barrier is external You need the internal heat of the room to keep the lower deck warm if you put more insolation under it it won't be warm and that could give you a problem

[@TheElectricbluey]

@@SteveRoofer Thanks for replying. Your a gent of a man. Much appreciated. I get exactly what you are saying, that makes sense to me. Good explanation as well.

[@the1only617]

Hi Steve, can you not use foil back plaster as vapour barrier??

[@johnp6636]

Good question

[@MikeNewland]

@@johnp6636 If the joints crossways fit closely can't see much problem. No airflow after plastering.

[@DSTGotchaGood]

With the vapour barrier in place can he still put in the LED downlighters or can you not pierce the barrier ? also if you put in a LED downlighter do you have to cut all the way through the kingspan or do you just leave hole halfway through it about 60mm?

[@SteveRoofer]

If you cut the AVCL you must repair it and make sure it totally airtight. If you downgrade the insulation buy cutting some of it away don't go to fare as you will get thermal bringing

[@DSTGotchaGood]

@@SteveRoofer Hi thanks for the reply, how would you "repair" it if you put in a downlighter is there a kit ?

[@paulpatterson1972]

I see some firms are building rooms with 5x3 joists and using 100mm pir. They push the pir up so it touches the underside of the ply and leave the small gag at the bottom of the joists and install a vapour barrier.. they claim this is a warm roof because the pir is touching the ply .

[@SteveRoofer]

No, it's not a warm roof or a cold roof. The ply will be as cold as the outside at night but there is no ventilation so not a cold roof. It's not a warm roof as the warmth of the room below is not warming the ply as the insulation is in the way.

[@paulpatterson1972]

So this kind of installation will cause issues due to sweating With no ventilation ? I’ve been doing some research into garden rooms and due to the 2.5 permitted height to avoid building regs it seems firms are using smaller timbers like 5x3 to avoid loosing to much headroom inside. Surely it’s just a case of using 50mm pir so to give an air gap and installing vents in the soffit boards each side.

[@SteveRoofer]

@@paulpatterson1972 Yes and no. 50mm is not that much insulation but anything is better than nothing also it's not so much the insulation that's the problem its the venting and the airtightness of t the build. The cavity above wants to be completely airtight from warm air rising from below. The void above wants to be able to vent out any moisture that gets up there. The thickness of insulation is only applicable to how much heat you retain unless it's so thin that it gets cold spots and you get thermal bringing and Interstitial condensation

[@paulavis]

Hi Steve - Great videos. Really helpful. I need to build a cold roof for my garden room (2.5m max). Noted the self-adhesive vapour barrier below the 100mm insulation/rafters and holes to facilitate airflow etc... and I saw you recommended insulated plasterboard (or at least more insulation below just above the pb) - what thickness would you recommend?

[@SteveRoofer]

I take it that 2.5 max is the height internally? Anyhow the amount of insulation under the rafters can be anything from 25mm upwards typically 25 to 50 mm normally the U value calculation on the thickness of installation above will dictate the thickness of installation needed below. I think that it's quite widely excepted that the minimum thickness of installation below to stop thermal bridging through the joists is 25 mm.

[@andrewliles7913]

Hi Steve great videos, I never thought roofing could be so interesting. I have a cold garage roof with 6 inch joists over a 3m span. The firrings for the first 3 to 4 joists are very thin, so I will have put holes into the joist. The roof is well vented at one end of the 3m span and at the last joist of the room into the remainder of the garage. What size and spacing of holes do you recommend for the first 3 to 4 joists. Cheers

[@SteveRoofer]

The only thing i can say is the bigger the better and the more the better but don't compromise the joists

[@Jonnysonone]

So what’s the solution for lights?

[@royfoster7010]

Hi Steve, Really interesting and helpful video. I’ve recently constructed a garden building. Block built then clad. I have a epdm roof (cold) My intention for it is a music studio. So having an air cap cavity in walls I put the doors on it last week went in today and the osb is soaked with condensation :( I’ve not got any venting yet. I was recommended to pack the joist with rockwool and then vapour barrier to seal all internal walls and roof so no venting. Is it ok to insulate while it’s wet? I’ve opened the doors to dry and it out. Any help would be very much appreciated. Roy

[@SteveRoofer]

Construction moisture lock just don't lock it in, vent the roof get it out. Cold flat roofs are good as they breath if vented properly. As regards walls again let them dry befor closing them and let them breath from the outside

[@royfoster7010]

Steve Roofer thanks so much. I don’t have any room for under soffit venting so was thing of using a number of trickle vents on the side of the facia (just the outer part) do you think this will be sufficient? Many thanks Roy

[@SteveRoofer]

@@royfoster7010 the ventilation in a cold flat roof is of the utmost importance you can never get to much so whatever you do overdo the venting, I always think about it like just having an umbrella over the insulation lots of venting from all sides

[@royfoster7010]

Steve Roofer Hi Steve! Thanks again for all you advice I’ve started cutting 40mm holes in my joists and put vents on the facias. The roof is now bone dry as I’ve left the doors open with a fan for the past week. My only worry is small black dots (mould) has appeared. Very tiny. Should I worry or do anything?

[@SteveRoofer]

@@royfoster7010 theoretically no as the mind won't grow if it can't get one of its foods and that's water or moisture if its dry up there then it will be dormant

[@dinger2490]

Steve, Is it possible to contact you for advice as I see by your video you have been able to offer support Thanks

[@SteveRoofer]

Yes call or email me any time v

[@SteveRoofer]

details are on the video or [e-mail] 07802300099

[@dinger2490]

I have sent you an email Steve

[@smsm4356]

WARNING: consult the NHBC guidelines before even thinking about drilling holes in your joists. Joists are there for a reason. Should your attempts to ventilate by creating holes of the wrong size or location, you will be compromising the structural integrity and putting lives at danger. "Bigger and better" is over-simplistic and gives no regard to the risks the home handyman or woman might be entering into.

[@habiburrehman3945]

Thanks waiting fo reply

[@SteveRoofer]

Reply regarding what?

[@xMarshy147x]

how is the wiring done for the lights if done this way? Im doing mine at the mo, as you cant make a hole through the vapour barrier

[@SteveRoofer]

You can but it must be sealed up properly

[@mikejones9992]

Could he also take the vents off. And spray foam insulation in every space.

[@SteveRoofer]

No then the roof wouldn't be vented

[@mikejones9992]

@@SteveRoofer what happens if it's not vented

[@Copeinked]

Moisture in warmer air naturally rises to to the vent space, if it’s not ventilated it has nowhere to go so will condense on the cold roof above and rot the osb or ply from underneath.

[@mikejones9992]

@@Copeinked right but it cant condensate if its sprayed with foam. Right?

[@Copeinked]

dude. wheresmycar This actually used to be the case when it came to building regs. No void, no air so no ventilation. But now many BCOs consider that just filling the void onto an insulated deck doesn’t constitute a warm roof and moisture will make its way through onto the underside of the cold deck and condense so a 50mm air void is regulatory and with a void needs ventilation. In theory you’re right, filling the void completely and dealing with expanding foam etc and then the addition of a vapour barrier would stop moisture.

[@garethmillers5453]

Thank you.

[@whatmouth]

Iko venting over deck simple

[@rideforever]

Vapour barrier contains vapour inside a dwelling. This is completely the opposite of the understanding of dwellings throughout history, we breathe and the building breathes, I think the entire design needs rethinking. These kinds of designs have very strange and unrealistic expectations of a house and are more about techo fetish then real working houses, these designs have very low fault tolerance and once there is a fault major damage. They are not robust practical real world solutions.

[@SteveRoofer]

I can agree with most of your statements above however in today's buildings we are insulating to a very high standard in which case we are not building the way we used to build and therefore we need to address what happens to the moisture we are trapping inside the building therefore we need vapour barriers now but we didn't many years ago

[@subzero3054]

Builder obviously has no idea about condensation issues which is the real problem. Drilling all the holes and adding a VB is also a load of nonsense, the correct advice would have been to install a warm roof. Roofing consultants should be promoting good practices and not how to get over one bodge with another.