The Old Mould Problem Returns - ASB #15

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Adrian Reynolds has black mold around his window reveals. He's tried cleaning with bleach, used a dehumidifier and seeks pearls of wisdom to help get rid of it.
Chris Stephenson would like to install a designer ceiling extractor over an island but is worried about fiddling with joists.
Ryan Thorpe is a 21-year-old bricklayer from Lincolnshire who just left his gang because of money problems and now self-employed working big sites. He needs to find someone to work with.
Will Laurie just moved house and has a wetroom/toilet in the garage. There is a sanishower pump getting rid of the water, but the shower basin fills up faster than the water leaves.
Richard Matzak had problems with a digital RF thermostat (Salus RT300RF) and changed it to a Nest. The problem was the radio frequency using the same as a neighbour's.
Zak Haque bought a house and is in the middle of refurbishing. He's partitioned the existing bathroom in to two, and is looking for fitters but has not been happy with the approach most fitters want to take.
#AskSkillBuilder #Mold #DIY
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[@chrisosh9574]

Excellent advice on this video to all questions. I am retired now but have worked in building and engineering for over 50 years. On the mould thing, use a proprietary mould cleaner, bleach will take it off but won't kill it.

[@SkillBuilder]

chris good point i forgot to say that bleach, when dry attracts moisture like a sponge.

[@ianwilde4704]

I had the black mould problem too. In my case it was the plaster bridging onto the outer skin. Chopped away a band all around the window, foamed it up and then replastered the reveals. Worked for me 👍🏻

[@sambotron84]

I know this was 2 years ago but how did this solution hold up? I was thinking about retrofitting cavity closer but foaming the cavity around the window reveals would be loads easier.

[@Neema1135514]

Hi Roger, I think that there is an obvious and simple solution to humidity problems, which is opening the windows each day in winter for about 10 and 20 minutes and in summer as much as you like. This will help tremendously in evacuating humidity and preventing mold development especially in old houses where you don't have a central ventilation system.

[@lazylad9064]

Its about the moist like Rodger said good air circulation is the answer. Can't believe we are struggling to get anyone to assist the bricky I'd have jumped at the chance thirty years ago. Too old now, but a great opportunity for some youngsters.

[@butryk22]

If the moisture has nowhere to escape, it will sit on your walls which will attract mould. It's pretty simple. Open the windows every now and then or invest in some good ventilation. No special paint, or sealant will tackle the root cause.

[@smartbuildengineering]

Trickle vents can be retrofitted to UPVC windows fairly easily providing adequate space on frame inside/outside.

[@shafserious2805]

Trickle vents are are pure nuisance! U dont need them, just open windows. TV always allow drafts into house which defeats the purpose of closing windows!!!

[@glennlockey1012]

Pumped waste systems normally have a small tank inside and when the water gets to a certain level the pump kicks in, looks to me like the pump is higher than the outflow from the shower. Drop the pump under the floor level and the problem will sort itself out. Great video as always

[@SkillBuilder]

There are other pumped waste systems that don't have a float switch. The start working when the shower is turned on.

[@Deegius]

Adrian Reynolds. - You're right about lack of trickle vents but als notice that the windows are placed right on the outer face of the wall. This means that a cold bridge is formed where the outer leaf passes over the window. The current obsession with air tightness and the poor design of placing those windows beyond the cavity are the cause of the problem. Open the windows and leave them open, get the air circulating and it will go away. Will Laurie, we have the same shower trap, it collects hair in the pot under the cover and needs regular cleaning, - we're both oldish and don't have too much hair left, but when our sons girlfriends stay, it clogs up quickly.

[@urielgrant2563]

instaBlaster.

[@johnf3326]

We had black mould and wet problems in window reveals and the wall above. Turned out the problem was solid concrete lintols above with 1 brick course due to roof rafters slope (so a single skin to the outside but behind the fascia boards. Sides were plaster touching the exterior brickwork, albeit through a good dpc. Solution, remove plaster and fix 15mm marmox board to sides and top of reveal and skim. The L section concrete lintol was insulated from inside the roof (with extreme difficulty!) With 1" Cellotex cut and stuck on with expanding foam. The alternative would have been to remove the gutters and fascias to get at the beams/wall. Redecorated. No subsequent condensation or mould.

[@petesims]

The mould problem could be where the old felt has fallen into the soffits and condensation is dripping down making a wet environment, by the look of those facias, they look like some rot has got to then. Felt lift trays and roof vent tiles should resolve that issue

[@BarriosGroupie]

I bet the windows with the mould problems are north facing. As you say, this is down to poor ventilation of condensation: One person asleep adds half a pint of water to the air overnight according to Octavia housing!

[@ratchriat1716]

found this video very informative and useful

[@Chanesmyname]

Love these help videos

[@98dizzard]

Not a problem with the cavity wall insulation, but the reveals haven't been insulated so you will have some cold bridging at the windows. Get some humidity measuring devices then leave some windows on vent position should help. 40-50% humidity in winter is good. Or as you say an extractor system. Reduce humidity sources and use any trickle vents or extractors. Almost every house I viewed when I moved has the extractors turned off in every wet room. Long term, next time the windows are replaced open the internal reveal a bit more and insulate it very well to help, combined with the other things this should do the job. If you've just replaced old leaky windows with new ones without trickle vents in either the walls or the windows then technically you'll be breaching building regs and any window fitter should know that.

[@98dizzard]

Oh and forgot to say, check the outside of the window has been sealed against the bricks or cold drafts will make the cold bridging worse.

[@Harryistired]

I agree with Roger but before I'd say it's cold bridging from what could be a concrete lintel which bridges the cavity which is less thermal heated as it won't be insulated, you could put in an insulated lintel ( too expensive). Also I'd check your cavity stops on the cavity tray above the window. MCIOB

[@SkillBuilder]

The upstairs lintels are eaves lintels with nothing on the outer skin but the timber wall plate. the real solution has to be to get rid of the airborne moisture, it is not healthy

[@Harryistired]

@@SkillBuilder oh my word, I do apologise regarding the lintels but yes some anti fungal wash asap

[@SkillBuilder]

@@Harryistired Don't apologise Jason. It is a discussion and all views and observations are welcome. The value of Ask Skill Builder is in the comments from others.

[@derekt7606]

How about a video installing a recovery system. Also if Mold was present in the US they would not live in the room.

[@davidjohnrobinson2887]

Mold present in my house, constant battle with it. Decided to try "anti condensation paint" early days yet and have not yet put any finish emulsion over it. The label reads use two coats. The product states it puts up a thermal barrier on cold surfaces. Not cheep at £20 litre though.

[@cho4d]

straight up snake oil. condensation happens when relatively warm humid air touches a relatively cold surface. how is a layer of paint going to change that equation?

[@davidjohnrobinson2887]

@@cho4d Ok here"s how it went. That winter after applying the paint i had no problems, after that back to normal. The mould happens about 18" above skirting level. The property has had lagging on the outside of the house. Rented property so it should not be my problem. Thanks.

[@latitudeash]

The brikey gang issue: I suggest he contacts his local college and goes to see them. Tell them he has two or three part time openings. This way he can provide two days a week training to them and have available one person to help him out for 7 days. The college will be biting his hand off as it is great on the job training for the kids. Also the government will give him a grant to wards that training he will provide to the students....it is a win win for all.

[@petemoring67]

Reading between the lines, I reckon that like MOST small contractors he wouldn't be able to 'afford' all that 'Red-Tape' and 'Health&Safety' issues that are blighting the industry lately :-(

[@latitudeash]

Pete Moring - red tape involves 6 monthly report on student progress. Good to prepare a simple set of skills that the student will undertake. If you run your own business it is not difficult. H&S is mostly about insurance, and proof you have a policy in place. It is worth doing. I think the extra time and effort he will spend giving training will still see a win win for his business.

[@petemoring67]

@@latitudeash The red-tape also includes being dragged through the 'Gig Economy' fiasco (Ask Pimlico Plumbers about that one) and Health&Safety insist on the '£££ purchase' of ALL of that totally unnecessary PPE gear which is the most Ironic working law ever sanctioned - as gloves, hard-hats and goggles etc, etc LIMITS the Spacial-Awareness of every worker on site. Hmmmmm??? :-(

[@benchippy8039]

Kitchens and bathrooms fitted to the highest standard- Buckinghamshire & Oxfordshire 😉

[@twmd]

The Cavity wall insulation can exacerbate condensation problems. firstly the insallers almost always miss large aras around the windows and under cavity trays which contributes relative cold spots . penetrating water can accumulate in cavity trays with mineral wool holding it there slowing the natural evaporation. Also it's worth pointing out that by exposing the CWI for the extention could be interepreted as distubing the CWI and void the 25 year guaratnee for the wool - also installing an extractor duct though the wall can also void the guarantee. absolute con. Insulated cavity closures would be preferred for new window installs but if it's e.g a concrete lintel above the windows then that is a difficult cold brige to solve. Hard to insulate it adequately but using a material that buffers moisture and naturaly mold proof can help. I'm experementing with lime hemp rendern for reveals as it is very alkali and naturally mold proof, provides some insulation from cold bridges and has excellent moisture buffering to cope with daytime variability e.g 2 occupants in bed.

[@r1273m]

I have a rental with the same mould problem. Whenever I walk past there is never a window open whatever the weather. This house appeared to be the same, all the windows closed tight!

[@SkillBuilder]

In rented places you have to have an whole house extraction system that they can't turn off. If you leave it to the tenant they won't use it.

[@Lord-Brett-Sinclair]

Skill Builder Piv fan work a treat for me around £500 plus fitting, and worth every penny .

[@SkillBuilder]

@@Lord-Brett-Sinclair good tip. We will investigate further

[@ek6868]

Tanx for the upload roger always intresting👍

[@ddel3901]

will stormdry cream prevent high wind driven rain from penetrating a brick home?

[@rebeccaa2097]

I don’t think you are right about the mould though. The house doesn’t have a chimney so should have been built to modern standards. Should maybe look at the way the windows are sealed and if they are using extractors in the kitchen and bathroom. The cavity may not be correctly done. Also why would that wood burner produce soot on the soffits/facias. What about exploring the loft insulation? Ask how long they’ve lived in the house?

[@samuelchamberlain2584]

Re trickle vents, yes they are usefull but realise the direction of flow is likely to be cold air in , not warm/moist out , depending on prevailing wind , stack effect and any extract/wood stove flue etc...

[@thomashawkins2395]

So Kevin witch heat recovery system would you recommend for a mid sized 3 bedroom house with on bathroom

[@kevinhancock4064]

Hi buddy watch a lot of your videos you're very into all trades great guy a quick question i have an issue 2 things 9ne 8s soare room lots 9f mould /damp/moisture around mostly the window side external wall , the wall joining thus has a vent that I've left open but don't seem to help much .....other issue being our front room right side reveal (right side from inside )keeps getting cold and moist is this likelynan insulation issue ? I can not see any 9bviois leaks from.ouysude but the windows do get condensation but left side isn't affected at all Thanks buddy

[@brianperrin8791]

Roger I know it’s a old post. But which is the best fan to get for the full house so no mold comes

[@logicallogic9960]

Fantastic advice.

[@shaunglendinning]

Great advice! Cheers.

[@taramiller70]

Do dehumifers and air purfier both kill mold spores and mold I have mold in my bedroom and I use dehumifers and I have plug in air purfier also do they both work and are they both worth using

[@aljroche]

Roger, do you know of any industry bodies which offer training courses for the bathroom system you mention?

[@charlespratt8663]

White vinegar works well, either pickling or cleaning strength ie above 5%.

[@eazyrat]

What product is it in reference to extraction talked about for the mould problem? Anyone reccomend? Thanks Roger Thanks Anyone who responds

[@Micah_Lal]

Very good

[@wes9384]

Hi roger, did you manage to make this list of recommended bathroom installers? We are looking to demo and redo our whole bathroom next year, but fear we lack the competence to do this ourselves XD We live in an area where we are not familiar enough to gain trustworthy recommendations yet (as we are new and don't know many people yet) and after having had a bad experience with a plasterer already, we are worried about whether we pick a good or again a bad tradesperson. Cheers

[@SkillBuilder]

I am afraid that project has stalled, It is still in the pipeline but may not get done in my lifetime.

[@wes9384]

​@@SkillBuilderO that might be a bit too late for me and I do assume you don't cover Stevenage XD We will figure it out. Thanks for your reply and great content. Cheers

[@carguillo1]

Nice one roger as aways next time your in stoneleigh Epsom dont forge that pint mate all the best/kevb

[@lukehanna3344]

Don’t understand why Bathroom fitters wouldn’t use the spec the customer wants? I always tank bathrooms & never had a call back, sometimes over engineered maybe but no leaks.

[@spongey76]

can you please help, just recently noticed black mould around pvc windows top and bottom of wall in corners and growing through window corner joints as well ,i noticed a drip from my gutter on back of house where the affected area is ,using long pole and camera i found my gutter was blocked and full of moss and water , can that cause the mould as ive never had mould in 20 years what would you advise

[@SkillBuilder]

I think the thing to do is clear the gutter and then see what happens. My initial thought is that it is condensation on the cold bridging. Put a couple of these on the window cill and see what happens. If they fill up fairly quickly then it is most probably condensation. www.amazon.co.uk/2562368-Moisture-dehumidifier-Condensation-Absorber/dp/B07XJ58SFX/ref=asc_df_B07XJ58SFX/?tag=bingshoppinga-21&linkCode=df0&hvadid=&hvpos=&hvnetw=o&hvrand=&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=pla-4584413743017114&psc=1

[@spongey76]

@@SkillBuilder ta much gutters getting cleared tomorow and ive got electric dehumidifier running next to bedroom window thanks again

[@petemoring67]

:-) :-) :-) What a coincidence? My daughter grabbed me Saturday to look at why her shower wouldn't drain propperly .... I got my nifty little brush we bought years ago to scrub the grouting, inserted it into plug-hole, twizzled it a few rev's and out came what looked like a drowned rat .... She hollered, but recovered when she realised it was only her hair :-) Re; the bathroom chappie not able to find suitable Bathroom Fitters - Often it's because the customer insists on an A1 job for C3 ££Money .... the two will never gel :-(

[@nedperry8527]

My friend had this mould problem tried every thing and was going to move house because of it , someone suggested a positive pressure fan and it worked , got rid of all his mould and has never has returned

[@fieldsofomagh]

What is a positive pressure fan ??

[@nedperry8527]

It's a small fan that draws air in from your loft , it runs all the time but is very quiet, it just increases the pressure inside the house only by a small amount but it does work

[@Lord-Brett-Sinclair]

Had the same in a terraced , worked a treat.

[@nedperry8527]

There is a video on KZbin it's called how to fit a PIV unit may be some help to you . I was very sceptical about it but he told me it done the trick, all mould gone and he was serious about moving he had tried everything it was doing his head in

[@GrandslamTim1]

I had exactly same problem, after a lot of research I bought and installed a Nuaire ECO Heat PIV (positive Input Ventillation unit) its a DIY job not complicated and its stoped condensation in its tracks, but be aware that you have to still promote ventilation so that stale air escape from property to promote good ventilation.

[@keithfrench9000]

I'm looking for a budget table saw, would you have any recommendations, thanks

[@SkillBuilder]

Hi Keith I haven't used anything other than the DeWalt and Milwaukee but I have so Triton tools and most are not bad for the money. Triton TWX7CS001 254mm Electric Contractor Saw… (9024R)

[@keithfrench9000]

@@SkillBuilder thanks

[@johnmorrissey1675]

Just one thing about mould is the position of the rads . When you have a rad under a window especially on the north of the building you will get a large build up of damp air when warm air meets cold surface i.e. window glass you hit due drop point . Plumber's need to stop putting rads under windows 👍

[@SkillBuilder]

Hi John We were taught in college that the best place for a radiator is beneath a window. The cold air drops from the window and is hit by the warm air rising so it warms it up and creates a very vigorous convection across the room drawing in more cold air from the room to feed in the bottom of the radiator. This can be proven with a simple smoke test. That said long curtains kill the whole thing stone dead so it has to be considered. Underfloor heating is what I now do. I have put a radiator in for ages.

[@johnmorrissey1675]

@@SkillBuilder I agree totally with what you have said it works in theory but not really in practice curtains or blinds of any type seen to debunk this idea I still think that when it comes down to it , stick it under the window out of the way , try and get a plumber to put a rad anywhere else but under the window it's like watching a bull dog chewing a wasp 😂

[@robmarrin6720]

That first video the two pipes going into the soil stack on bosses look 21.5 overflow pipe I've never done that before

[@SkillBuilder]

It is done for condensate from boilers as well as Saniflo. Better is a 32 mm boss and a reducer. That looks like it is bodged in with silicone.

[@ShadowzGSD]

Tip 1 - so many people dry/warm towels and clothes on radiators. Nooo, where do you think the moisture is going, don't do it. Tip 2 - most windows can open a fraction and still lock, do this and it lets each room ventilate if there is no vent on the window. Tip 3 - so many people have extractors with no humidistat built in or leave the extractor fans off because they make a little bit of noise, fit a decent extractor, the best you can afford (cheap ones are rubbish with a very low extraction rate) with built in humidistat so it can clear the moisture out. Tip 4 - put a bowl of salt on the window sills, they help absorb moisture out of the air, you can make it look 'pretty' if you like by adding a few pebbles or using a decorative bowl ( be carefull in kids bedrooms and probably put on a wardrobe nearest window so it is out of reach )

[@leeholke9851]

Wash mould 1st Dont use de hum with mould because it will spread. And wash mould with warm soapy water

[@eugeneeugene8252]

Very much true about bathrooms (and almost everything else) Roger.In fact I happily give away £200 if you show me what I call 99percent job

[@Eric-rz2xb]

Cutting a ceiling joist isn't necessarily that big a deal. We do it all the time. Often less work than that drop ceiling you show. Just be sure that before you go cutting ceiling joists that you consult with an engineer first. There are many strategies available for doing it correctly dependent upon the particular situation.

[@yensabi]

Leave the small window open a tiny amount and that will solve the problem , it worked for me and mine where really bad....👍

[@mannysandhu2003]

Gordon Ramsey of building

[@MrBarrytommy]

Roger is so right me thinks , 'Hair' is one of the main shower blockers

[@troyboy4345]

Ah yes the old mould returns, good to see you back Roger … the better looking of the dodgy pair of so called professional tradesman … the other one is …… ???

[@Dragon-Slay3r]

😭

[@LeakyJim1]

Struggle finding bathroom fitter. I always think its as easy (or as hard) to do a job correctly as it is to do it incorrectly, it just takes longer. My problem is finding customers that want to pay for that time, when you get one its great, best feeling in the world doing a good job for a good customer at a good price. Most of the other plumbers I know just want to boiler bash, easy money, in & out and on to the next job. They can prob earn double doing that than bathroom fitting. Good for the wallet but oh so dull.

[@ShakaTee]

Ck