The Hidden Dangers of Mould: Exposing High Humidity & No Ventilation
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- Опубликовано: 27 сен 2024
- London flat roofing
07802300099
info@londonflatroofing.co.uk
I did a roof inspection on this property in London on a cold day. As you can see in the video, the relative humidity in the property was very high. The cold roof was not vented correctly, and there was a clear path for warm moist air to get up into the non-vented space. This was then condensing on the underside of the roof decking, running down and landing on the plasterboard that forms the ceiling. No Air Vapour Control Layer (AVCL) has been installed. The spotlights are big holes in the ceiling that are letting warm, moist air directly up into the unvented cold roof. The water damage is so bad that water is dripping from the lights, even when it's not raining. The insulation is too close to the spotlight in the ceiling, and you can see that the insulation has burnt because of its close proximity. Realistically the entire roof should be stripped and a warm roof should be fitted. However, sometimes this is hard to do because of height restrictions with warm roofs, but on this property it's not the case; a warm roof would be the way to go. I went up on the roof and the decking, although wet and covered with mould, is still sound as it hasn't rotted away yet. Will it dry out if venting were to be added? The answer is yes, but the mould in the roof void will still be there and may always be a hazard. Changing the roof and keeping a cold roof would mean that the ceilings would have to come done to be able to deal with the mould in the roof, also to be able to fix an Air Vapour Control Layer (AVCL), and then the ceiling could be re-installed but with a void for lighting. This would drop the height of the ceiling in the rooms.
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Steven Dickinson
London flat roofing
07802300099
info@londonflatroofing.co.uk
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Great video, you are the main man in this field!! Keep it up mate
Thanks
It always give me a buzz when I see RUclips legends on each others channels. Love you all man x
Gold standard content, recent sub and thoroughly enjoying watching your videos!
Thanks
Chudley Construction handbook is good for general knowledge of all roofs and more. Worth buying and downloading .
Yes doing reference before building is alway a good thing
I've seen similar issues - condensation so bad it looks like a terrible leak - but it made me think the same roof in a different location would have had a different affect. But it was a cold roof.
Location has a lot to do with it. If the property isn't getting a lot of sunlight then there's more chance of it staying colder for longer and therefore sweating, so even a bad roof in the right location can work.
I’ve been doing roofing for about 4 years now. And constantly find myself working for cowboys. Obviously I have to bite my tongue when certain decisions are made in terms cutting corners. But where the f**k can I find someone like you to work for who can actually teach me the science behind roofing and actually cares about his reputation. I know I’m not ready to go out on my own but I constantly feel like I would do a much better job at a much lower price than these donuts who are only in it for easy money.
You want it, it'll come to you fella! Don't be afraid to keep moving forward. You sound like a diamond, no reason you won't find yours in time.
Yes, your time will come keep at it. What kind of roofing do you do?
Reading a book is the simplest way to get the right knowledge. I have not read any in English. But I believe “ Moisture Control for Residential Buildings” would be a good start. Furthermore, you can start your own company if you manage to get the right consultants that has the knowledge you are lacking. A good engineer should have the right knowledge to be able to make plan of action.
@@arvidjohansson3120 there is one man out there that i get a lot of info from and the best thing I can do is get you to follow this link to one of his videos there all long but worht watching ruclips.net/video/IaozbiujnWM/видео.html&ab_channel=RooflogicLimited
Where abouts in the country are you? I’m looking for new people who want to learn the trade properly to join our team
👍 good job
Thanks 👍
ventilation is the key👌
Yes if everything else is wrong then the venting can save the day
@@SteveRoofer hi Steve am I able to contact you in regards to a query I have
Wow, that's nasty. Drying clothes inside can be a real problem - maybe a dryer/de-humidifier should be considered for such cases.
Old houses, like your granny used to dry clothes in, must of been rather well ventilated, with all those windows thrown open for the fresh air..
Yes, ventilation is the way to go
It like those in the building trade are really bad communicators bar the odd few educators like yourself.
We need to start a version of the scouts but for builders.
Short courses for which you get a little badge to show your proficcencys.
Today Dave completed his warm roof knolage badge.
Nobody is trained anymore it's no wonder things are the way they are now
Hi Steve.
Great video, thank you for your uploads that help viewers out like me.
My builder did a cold dormer roof without vapour barrier and didn’t put any vents, so the roof is sweating and making marks on ceiling just like in this video, if I add vents on facia board on every centre would that help??
Make cure the ceiling to the rooms below are air tight remove spotlight add venting above that as much as you can do
Thanks for the video Steve, it's been a while, miss your content. What's the outcome of your survey. You gonna fix it?
No, all I was doing was a roof survey as they thought they had a roof leak. I think the customer doesn't belive me and still thinks there is a roof leak
Evening steve! Thank you for sharing your experince and work. I am in the process of insulating my loft conersion. The architect specs have specified insulation and vapour control barrier. As you have mentioned the architect has not specified what vcb is to be used. Could you assist me with what vcb i should use and whether i have the correct ventilation provided by the builders work? Thanks.
Slightly different question, but i wanted to ask it on your most recent video so you can see it. On a warm roof you talk about putting extra plywood on the top the insulation to prevent it being soft, but how will you secure it? You can’t screw into the insulation to secure the plywood? Great videos
The results of 'drying' clothes indoors is partly (mostly?) to blame here. We all do it but clothes horses should be banned. I wonder if the bathroom had an extractor fan.
when insulating a solid brick wall with no cavity. do you need ventilation behind it? like air bricks to bring air from outside to behind the new insulated wall?
On a solid brick wall you would not vent it are you thinking of insulating externally or internal?
@@SteveRoofer insulating internally
because say if i build a stud wall slightly off the wall. does the gap need to be ventilated. the reason i ask this is because under the joists on a ground floor usually has air vents to outside? so i thought i would need the same thing behind my new insulated wall
@@user-cn1em2qx6f the reason you have air vents under joist is to have air movement. When air gets hotter inside a dwelling it can hold more moisture in it. As the air gets cooler it has to shed moisture. Anything below the dew point and moisture will condense on it. The air moving across it will evaporate the moisture back in to the air, but you need the air movement since the now colder outside air can’t absorb much moisture into the air. It’s not enough to just put in some air bricks and hope, you want to design in some air movement.
The problem with your situation is that you will cool the wall potentially leading to interstitial condensation. I would say the key is to make sure your environment is a dry as possible and make sure you do a good job on a vapour control barrier.
There are calculations that can be done but that’s not my area of expertise.
For the room the more you can get fresh air in that’s lower humidity then the less moisture in your air. The minimum amount of moisture producing activities the better. Ie cover boiling pots and pans, extractor in shower, remove moisture from shower walls with a window vac, don’t dry clothes indoors, open your trickle vents, etc.
@@davideyres955 thanks for reply. really helpful!!!!
Hi Steve, I hope you can advise, I have a garage made with prefabricated concrete panels, which I was going to turn into an outdoor office, it has a flat torched on felted roof, my intention was to build a sloping roof on top of the existing roof. i.e. leave the existing roof as is and build the sloping roof directly on top. This would slope down from approximately 12 inches to 2 inches which would create a void (air gap). On the internal underside of the original roof, I was going to use insulation between the joist then cover this with a vapour barrier then plasterboard, will this cause me problems with moisture forming.
Any help or advice would be appreciated, you have no doubt gathered I am a novice at this type of work.
Thanks
Hopefully the help I've been giving you by email has solved the problem. Speak soon
How frustrating. This could have been easily prevented with closed cell spray foam on the underside of the roof deck and a decent mechanical ventilation system & dehumidifier. Either that or just have all exterior insulation on the roof deck to warm up that condensing surface + the mechanical ventilation & dehumidifier.
Yes this could have been managed better but its all down to bad building practices
Hello Steve, i did my old house roof with hard insulation sheets, i left a gab between roof and insulation 3cm, air is flowing there. And i had air flowing from outside. Still roof is old and i couldnt put sheets properly with no air coming from outside. So i put aluminium tape between sheets and i wood, is this wrong?
Great vid, would you just suggest to put in thermahoods above each light fitting? Would this be enough? If not what type of vapour barrier
airtightness is more important than the AVCL so if you are only going to do one thing add the hoods
@@SteveRoofer could you recommend a tape to go with the Thermahood. DuPont - Tyvek Double-Side? Or is that overkill?
@@dwainDigital As I don't do cold roofs, I don't know of any perhaps when you find one, you can tell me about it so I can pass on that info
Hi Steve, another great video. May I ask what inspection camera you are using? It's just what I'm looking for! Thank you
what part of the vide as I used two or thee cameras a go pro 10 a mobile phone a flir IR camera for I phone
@@SteveRoofer Hi Steve, Many thanks for your speedy response - I should have been clearer. By deduction I realise it' the Go Pro 10 for the footage I meant. Keep up the good work
@@okitwas5seconds I have two and have hade serval over the years but wont be using them for much longer as now the insta360 approx same price but works without overheating and all the software problems can be used as a gopro and as a 360 camera, generally a lot easier and much more options to choose from
What is this tool / camera brand you are using to take the video inside of the light hole (enabling you to video in between the flat roof?
Would it help if they added some ISO insulation on the top of the roof?
Yes you could turn this into a warm roof by adding lots of insulation on top, problem is without striping it would you want to spend loads of money on a new roof and inspiration over that lot!
Hi Steve, do you mind me asking what in your opinion is the best performing vapour barrier for a warm roof?
Hi Steve,great videos thanks for posting,I'm putting a flat roof extension on a bungalow,can you tell me if I can vent a cold roof through the bungalow loft space...thanks ray
I don't think anything is saying you can't, but I wouldn't keep them separate you don't want moist air from one going in the other Plus building regulations talks about the though venting on a flat roof should not exceed 5m so the length of the roof and the length of the loft space till you get to the next vent will be to long
Thanks Steve, warm roof it is then...👍👍
Hi Steven enjoy your video I have question in relation to my roof, I have in the attic between the joice 100 mm wool insulation, I what to replace it with 100mm aluminum foam insulation is that ok? And also to put this old insulation in between the rafters of roof and secure it with membrane. What do you think? Thank you for advice.
Wool breathes, so at the moment the loft area is breathing, change it with a PIR insulation in the loft won't be breathing so; therefore you will need to think about what you're gonna do with all the moisture that may build up in there personally, I will always keep something breathable if I could
@@HampsteadBuildersLt thank you very much for your advice Justin
Hi Steve. We have a "warm deck" flat roof and noticed a condensation leak only during the summer or hot weather. I've found the edge of the insulation board wet with a few drops if I push my finger into the yellow material. Would this be soaked ALL the way through like a sponge or would it just be the edge?
There is no answer to that it could be it depends on how bad the situation is. I have seen it so that it's absolutely sodden. If you want to send me some photographs or a video of it I'll certainly have a look steveroofer@gmail.com
Hi Steve, We're currently planning to convert a flat roof from cold to warm. We've been advised to keep the current 100mm insulation and keep the airflow open for 9 months to dry the roof. Question is, I saw your video about these kinds of conversions and you mentioned that the old insulation should be raised up under the roof, but the offers i'm getting all say that it does not matter whether or not the 100mm insulation is raised... they would just leave and keep air space between roof and old insulation. The warm roof we're converting to would have 200 or 300 mm.. Whats you take?
What you're talking about above is slightly confusing. I'm not sure. I understand the full question. You do not vent under a cold roof. You always have 2/3 of the insulation above the vapour barrier. That's the golden rule. If you need more information email me over photos and the only thing you have, and I will have a look.
Hi Steve im currently doing a cold flat roof on our extension which is 4.8m out by 12.5m wide. In your opinion is there a size limit for a cold roof in regards to getting vented air through it? I will cross batten and have vented sofits all around and a 25mm vented upstand against the house.
Many thanks
If the roof is over 5m wide they want it vented in the center. 50 mm is the recommended depth for the air vent. I would never do a warm roof as even with venting they don't work anymore I cover this in my last article in roofingtoday
@HampsteadBuildersLt
Thanks Steve I'll try and find that article. Do you stay away from warm roofs all together now then?
So if i put some mushroom vents halfway i should be good then?
I currently have 50mm ventilation between joists (9x2) with firring strips and 25mm cross battens on top.
Thanks for your help and your videos have been great 👍 👌
@@HampsteadBuildersLt could you kindly put a link to your article if possible?
Many thanks
I stay away from cold roofs. We only do warm roofs cold roofs are troublesome the more ventilation you put into a cold roof the better
Was there no extractor fan in the bathroom? Also what what you say as a good humidity level in the home to aim for? Thanks
between 50 and 60% is the best and yes there was a fan
Hi Steve, I would appreciate your advice. Is it okay to apply epdm directly onto foil-backed PIR insulation or should a OSB or similar be used on top of the PIR. Thanks.
Hi - EPDM can be applied directly onto PIR board that has fibreglass tissue (such as Kingspan TR27), but not onto a "normal" foil-backed PIR. In your case, OSB should be used.
Why have they cross battened but not vented? I thought cross battens were for ventilation
Just discovered your channel Steve and watched your video on cold roof ventilation.
I'm currently doing a dormer loft with vented cold roof so this was perfect viewing! I'll be having a good look at your other videos too. Great channel!! 🙏🏼
very interesting 👍
Thanks For me, when I see something like this, it makes my day but unfortunately not for the people involved
@@SteveRoofer Agreed, very depressing for the customer, at least they understand the problem now, an method to solve it.
Is this a cash job
Sorry don't understand the question