Damp, is inside your cavity causing problems like this?
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- Опубликовано: 28 авг 2017
- We had to replace the sub floor air vents around this property in Barnsley, S.Yorks with plastic super flow ones after issues inside with the sub-floor ventilation. Damp Sam shows what happens to cavity wall insulation when it is installed incorrectly.
I’m on my second time owning a brick house . I’ve learnt a lot since owning a brick house . One thing I would never do is insulate the cavity . It’s there for a reason . Of course an insulation company will tell you otherwise but they certainly are not builders or brick layers . If you need more insulation then buy another house but don’t fill the cavity because it’s not a matter of if it will get wet but when it gets wet and now you have a major problem on your hands . The other thing is painting brick ! I have no problem with it however you should stain it rather than paint it . Mortar is porous and to my mind sealing it off can only be beneficial and let’s not forget your only painting one side out 6 so where’s the issue . Any moisture that may occur on the backside of the brick is taken care of by a well functioning air cavity . Simple .
I haven't installed yet, but am looking to first put a semicircle of expanding foam in around the air vent, in the cavity, to enable the exchange of air underneath the house, but not in the cavity. I would also ensure that adjacent to the vent under the house, you leave a gap in any floor insulation.
Also, you can get maps of the extent of driving rain. There are some regions with moderate to high levels of driving rain causing the bricks to get wet. This is not great for cavity wall insulation.
Its good to see your not hating on cavity wall insulation, so many people blanket all CWI as the same crap but its not, the stuff these days is so different. Its now non water absorbing preventing bridging between the inside and outside and is structured in such a way that water and air can pass through the gaps no problem. Now, that cotton shit, get that out asap.
Totally agree, it’s the polyurethane loft insulation that’s not being installed or surveyed correctly at the moment
@@dampsam ye pir board is really good stuff maybe even the best but I've seen people install it over the loft joists, which doesn't allow them to breathe. I would just use it between and then cover with mineral wool for breathability. Don't even get me started on the spray stuff tho.... That's a wild west.
Appreciate your reply. I understand that the houses that don't have timber floors don't have vents but what about bedrooms. I see a lot of houses with air bricks and then others that don't just wondered if there is a reason? Sorry for another question. Cheers
Pete Goldsmith no worries, again it’s the design and age, a lot of ex local authorities property had vent in bedroom, and it may have had something to do with open fires in the bedrooms , a lot of these got blocked up over time, vents were also needed for gas fires when they came out too.
Have a property (a ground floor flat) which has had cavity wall insulation at some point in the past. It is a cotton wadding type material. We had an issue with the DPC being breached with soil (has since been removed to 150mm below the DPC) which we believe lead to condensation on the inside of the walls in the winter. So far, the weather has been pretty good this summer and I'm hoping that any moisture that was soaked up because of the DPC breach will soon dry out. My question is, should I add some weep vents above the DPC to potentially aid in air flow? In your video you mentioned sagging, this won't have happened below the windows but agree this might have happened on the side of the property.
One of the issues with the cotton wool type of CWI is there is more than one way for it to become wet, water vapour travelling through the fabric as a gas to the outside can wet the material so the ventilation inside may need to be looked at.
@@dampsam you mean ventilation within the property, i.e windows opened or upgraded to the ones with the vents in them?
@@Paul-dr8tq I would assume so. Frequent opening of windows/trickle vents on nice dry days, automatic extractor fans in all rooms that have either a bath or shower in them, extractor fans always used when cooking on the hob, not drying any clothes inside the house (i.e. pegging them out on days with decent weather & using a tumble dryer that is either a condenser or externally vented on days you can't peg clothes out). It's all simple to do. It always surprises me when a person complains that their house feels too humid, then when I walk around the place there's thick towels and jeans drying away on their central heating rads 🤦♂
Hi Simon I was looking at getting Cavity wall insulation think it would have been the beads type is it recommended or just leave the cavity open?
Cavity wall insulation is fine if it’s done correctly, you just need to make sure the surveyor knows what he’s doing and is competent
Hi there, thanks for this. We get a lot of cold air in the bedroom and we've got these cavity bricks in the wall. Would it be an issue with these or windows? And how could it be fixed? Thanks
Without more info and a site visit it would be hard to say
Hi, great vids, I have a question,
I have the exact problem where the cavity wall insulation is causing bridging and shows up as wet patches on the inside wall where dot and dab was done on plasterboard. Questions are:
1) I intend to remove the nasty insulation from the inside by slowly taking out 1 brick at a time, and using hoover etc, do you have any better techniques?
2) will replacing it with expanding g foam be better or shall I leave it hollow?
3) will applying stormdry to the outside wall be sufficient and save the need to remove the cavity wall insulation as it is quite a laboursom task
Thanks
Hi, the first thing I would say is if your going to remove the cavity wall insulation get a company to do it as you might go through quite a few hovers. They have the right equipment. Check if you have any time left on your guarantee as you may be able to claim. Don’t fill it with foam as this can cause more issues with interstitial condensation. StormDry will stop water penetrating but you need to make sure all the pointing is sound before applying it. Hope this helps.
@@dampsam excellent, thank you for the advice, really appreciate it.
Rescue and repair existing of cavity wall insulation
@@dampsam Can I ask you how we can tell for sure the soundness of the pointing? My house was built in 1946 and appears to have lime mortar. It seems okay, with just a little pitting. I wanted to put StormDry on it but was concerned this wouldn't allow the bricks to breathe (?). Thanks!
Hi there just wondered why some houses don't have air bricks at all. Looking at moving house and noticed that some don't have any air bricks in the cavity walls. Thanks.
Pete Goldsmith it depends on the construction of the property and age as they are all different method.
Timber floors need subfloor vents but solid don’t .
Some properties had vents for rooms as did pantry’s and cellars.
In later years some people vented the cavity too.
Hi Sam, I recently moved into 1950's bungalow that had cavity wall insulation installed sometime ago. Im trying to get the certificate from CIGA to see when it was installed but all the airvents in the house are blocked up with silicone and all the airbricks outside have also been sealed up?
Ive got damp on the inside of the house on all internal walls particularly at the bottom of each wall on the ground floor but not so much as you go higher up the wall. Some of it will be attributed to no DPM in the concrete floor slab (marley tiles and bitumen only on top I discovered when had sulphur test done). The dpc in the walls my builder says is absolutely fine and all intact. My builder said if the cavity wall had failed it would all be sagged and wet at the bottom of all walls. I had so called cavity wall specialist to come and check the insulation to see if it had failed and all he did was run damp meter over the walls, tell me Ive got rsiing damp and sent me a quote for £4K to put it right - e.g. inject all the walls including a plasterboard stud wall!! he didnt even remove a brick to check what was in the cavity. I found out he'd only been in the job two months and previously worked for Asda! How do I get the cavity checked as dont trust anyone - had 3 companies out now and all did same - jujst want to rip the plaster of the walls a meter high and inject but thats not the solution without finidng the cause for me. Can you help point me in the right direction, or advise on a good local company? Can I check the cavity myself by removing a brick to see if its wet. Im in Kidsgrove, single female 'diyer' so dont mind getting stuck in. thanks
Hi Andrea, it’s the type of cavity wall insulation that’s the issue, white cotton wool type that holds together when you squeeze it. It also needs to have been installed within the last 16 years I think. You could take an airbrick out and then replace it with a super flow plastic one, when the clay one is out you will see what type. You can email me at dampsam@thedampshow if you get stuck
What happened with your situation? Did you resolve it?
Hi, why has that wall got a line of vertical damp proof injection homes? I don;t get why you'd ever want to go up the wall like that.
It’s to stop lateral damp, it’s part of the system of repair
Rescue and repair existing of cavity wall insulation
Hi there, would you advise to put cavity insulation back in? If so could it go below dpc? I’m asking as I have done this job and a builder has told me it could cause cold bridges… your opinion would be lovely cheers
It can’t cause a cold bridge if it’s a modern insulation, the older insulation could become wet but the new stuff should be waterproof
@@dampsam ok brilliant thanks for the reply, the house is 1960’s so the insulation may not be waterproof?
So am I correct in saying that if I didn’t put any insulation back in it would still cause mould on the inside wall due to cold surface?
Thanks for your reply mate, these bits of knowledge are vital when it’s diy thank you!
I mate I have seen these cavity wall vents you just drill and push in will this help by let air in and out of the cavity
Wayne Dean no the passyfier vents are a sealed unit and they don’t vent into the cavity
I have the polybead stuff, is that ok?
Yea it’s ok
Hello my house is really cold without heating on 12 degrees and not warming up with heating on cavity wall was done in 1997 does it need re doing?? Pls reply back thanks
Without a site visit I couldn’t say what your issue is
You can NOT add cavity-wall insulation into a cavity-wall that is already built.
Cavity-wall insulation can ONLY be installed from the VERY START of construction of the cavity-wall.
Ok
Is it normal for a cavity to be damp, thanks
Stephen Livesey the cavity will get wet as water vapour travels through it, but some cavity wall insulation will become wet and this can lead to bridging.
So you've diagnosed the issue then just water proofed the inside instead?
You can NOT add cavity-wall insulation into a cavity-wall that is already built up.
Cavity-wall insulation can ONLY be installed from the VERY START of construction of the cavity-walls.
If cavity-wall insulation is to be used there must be a LARGE air space gap in-between the face of the cavity-wall insulation batt and the outer wall inside the cavity, this includes an air space gap in-between the face of the cavity-wall insulation batt and the cavity-wall-tie drip point-which is in the centre of the cavity. Cavity wall ties are laid with a slight downwards slope from the inner to the outer walls. Ask city & Guilds N.V.Q. BRICKWORK teachers for PROOF of all this .
There are lots of types of insulation
Hi im having trouble with my cavity wall insulation on the gable end but what i have only just noticed is that they have sealed up my air vents with silicone (7of them) is this normal? And should i clear them as im getting damp in my bedroom on that side...cheers
farnyone are the air vents for a Timber subfloor? Or are they into the cavity wall,
If your insulation was installed in the last 14 years you could claim for damage and get it re-done free. If you want to email me with your details I can look into it. Info@alldrydampproofing.com
Rescue and repair existing of cavity wall insulation
cavity walls needed maintaining.... I hope that was the solution? very easy to do.
electronurd yep I get what your saying but out of all the different solutions you need to pick the most viable.
Rescue and repair existing of cavity wall insulation
Aibricks need protecting - this was a faulty install from the start as are most of them done in the last 25 years. If it's not causing damp it's more luck than anything as standards and surveys were very poorly overseen.
its not the lads to blame its the Managment they push and rush the lads to cut corners don't you miller Pattison you no who you are ;) (sig) Sheffield insulation group ltd.
that be installed by miller Pattison cowboys
🤷🏻♂️