Condensation in roof voids

[@mrkeogh]

This is the best breakdown and explanation of why condensation occurs in older roof spaces, and where you're likely to see it. Bravo! Very helpful 👏🏻👏🏻👏🏻

[@TheWebstaff]

No way that explains exactly whats happening in my garage roof space. Thankyou so much for sharing this info!

[@TheRowerzysta]

My loft in previous house was an exact copy, felt was dripping wet. I fitted lap vents, pulled the insulation out the eaves and fitted soffit vents. It dried up in a few days and was problem free.

[@Alanna-d7v]

Have U tile roof vents

[@jasondoyle1037]

I have a similar situation. In the cold winter weather I have droplets of condensation on the underside of the bitumen felt. There is no roof ventilation , neither at the eaves or ridge. The ceiling glass fibre insulation is at time soaking wet. In the house (bungalow)below humidity levels are always very high even though I am the only occupant and am very careful to always try to minimise the moisture I create. Is it possible that I might lower the humidity appreciably in the house if I improve my roof space ventilation?

[@1971dave]

Don't waste your money on those vents, just feel for the batten underneath cut a triangle facing down and then tuck the point back in the batten,

[@adsheff]

How far back did you pull insulation? Do you pull it back so that the ceiling is fully exposed?

[@davideyres955]

@jasondoyle1037no you won’t decrease the humidity in the house by sorting out the loft. The loft is the result of you high levels of humidity migrating into the loft and that moist air hitting something colder than the dew point of the humidity and the water condensing. You need to reduce the moisture in the air in the property and make sure you have ventilation in the loft. The ideal situation would be fitting a vapour control layer at the ceiling to reduce the transfer of humid air to the loft but that is expensive and disruptive. Even having a drafty loft may not be enough if you continue putting a lot of humid air up there. You could try a very non porous paint on the ceiling. 1 st thing to do is get you’re self hygrometers and check the humidity in the rooms. Govee do some nice e ink ones. Open the windows to let the air in the rooms. Especially when it’s cold outside. This will let colder less water laden air in to the house. As you then heat this up the relative humidity will come down. Then get the loft sorted with either eve venting or another type of air ventilation. The insulation you have in there will be shot so it will need replacing. Look into Passive input ventilation or mechanical ventilation with heat recovery MVHR. Think about a dehumidifier and try to minimise any moisture adding activities. Drying clothes indoors, fish tanks, cooking with no extractor fan that is connected to the outside.

[@lakeswildcamping1981]

I had an issue with roofing felt condensation but fitted lap vents and this has improved air flow greatly.

[@retrofuzzuk3672]

I have a south facing house too. I also have condensation at the rear too! Thank you for this

[@Kizzerfordpintoplowright]

❤ very very helpful good knowledge. 😊

[@AyupStuggy]

Fit felt lap vents internally. They are cheap (£20 for 10) and install each in less than a minute.

[@adsheff]

I have the same problem. However worried about adding more vents as its in a very cold area that frequently gets heavy dews. What that cause problems?

[@27bri27]

Would it not be simpler just to remove the insulation from the eaves?

[@roymichaeldeanable]

Exactly...let the building breathe

[@rosslotus8214]

I've got carpet layer under my insulation could this cause condensation?

[@markhughes2423]

My loft had plasterboard over the rafters, and behind them was the bitumen stuff. The plasterboard had become very damp but hard to say if it was caused from the space between plasterboard and roof tiles.

[@marcharrison9819]

Would lap vents not be a cost effective solution? No need for planning permission either.

[@brookfield8413]

That insulation need pulling back at eaves /wall plate level, as it looks like it’s touching the old felt which causes big issues. Fitting a dry ridge system and opening up the felt on ridge level plus over facia vents are another way of getting the roof to vent, could be done without planning permission??

[@philipoakley5498]

Excellent. It's like the effects that Dr Joe Lstiburek notes where folks had painted their walls/roof and suddenly got a load of moisture problems 'cos they no longer had the solar heating & drying effects (PS the guy's Canadian, and the physics is world wide, don't let the 'USA' perceptions fo0l you if you watch his lectures 🤔).

[@TheD7035]

thank you very helpful.

[@patterdalezipsuzilil]

I used to get condensation when I had a living flame fire in a open stack the stack was allways warm so I put 2 roof vent tiles in 1 near stack and one at furthest point on bk roof and fitted an inline duct fan and a humidity stat never had it again

[@a_planet_on_fire]

Does the inline duct fan prevent backflow of damp air? Thx

[@johncranna]

I'm a structural engineer and what I'd also be most worried about is the lack of any bracing to the trussed rafters. There is no longitudinal bracing nor is there any diagonal bracing and the design assumptions of restraint of the trusses at the node points is invalid here due to the lack of bracing.

[@onanysundrymule3144]

I can see a diagonal strut at around the 1:30 to 1:34 min mark. It does appear to be of slate batten type scantlings though, ie better in tension mode than in compression for sure.

[@johncranna]

@@onanysundrymule3144 Yes, you're right. You can see that bit if diagonal bracing at the beginning. The trouble is that it does not carry on along the whole length of the roof which is what it should do and there are no longitudinal braces at node points so still a fail in my books.

[@1971dave]

Structural engineer on your grandad's side, you're talking complete nonsense, we are a building and Engineering Company tell you what dude send us your email on here let's have a look at your credentials it's a listed building and no doubt their supporting walls, some people on here see a video and then they comment on another video like this ​@@johncranna

[@davebatman847]

Manthorpe lap vents, wont have to apply for planning permission then, strip eaves and install rafter tray(its corrugated and keeps the insulation from touching the felt)

[@Pompey701]

My house was built in the mid 90s the rear of the house is full south facing the ceilings are fully insulated and there is open space into the eaves with full length vented soffits and i still get condensation dripping from the bitumen roof felt.

[@onanysundrymule3144]

You heard the guy, you will have to turn your house around so that the front is South facing. Could be expensive. Only joking. Have you ensured that you have full through and cross ventilation to the eaves on both sides?

[@Pompey701]

@@onanysundrymule3144 brick gables East and west facing, tiled roof north and south facing, full width vented soffits in the eaves on North and south elevations no obstructions can feel the breeze when it's windy but condensates when the temperature outside is very cold.

[@jasonedwards2852]

My ceiling above bathroom has brown stains on it and been up to loft and roof liining is wet could this be causing the stains on ceiling ?

[@mrkeogh]

We have brown staining on the new insulation from where condensation on the bitumen felt is dripping down.

[@Thurmatron]

A listed building with fink truss and concrete block walls? Great video tho.

[@tomvincent5596]

Interesting stuff 👍

[@williamkennedy5492]

Today Nov 22, i took our crimbo decs down from the roof space, AND took a look at the inside of the roof , not only condensation but white powdery deposits on the roof beams, I think its the start of dry rot, and it will need treating, I do believe the insulation has also been pushed down into the eves area hence no airflow. Clucking bells springs to mind,

[@neilspeers5578]

How much mate and what vents I'm south facing house?

[@240soundwave]

First thing to do is pull back that insulation see if the problem goes away?

[@Toyotaamazon80series]

Agreed plus installation of soffit vents. They are reasonably discreet and may not need planning.

[@adrianchen1423]

What do you mean by pull back? Like pulling it away from the edges?

[@kitrssurfer9185]

@@adrianchen1423 yes because in the eaves are usually the vents and you need air flow in the loft from outside

[@EggsForDessert]

Could you recommended a good company in Birmingham that might do the same as yourselves?

[@carolemccartney566]

Remember the moisture in the roof space comes from the house below! Don’t dry clothes in the house!

[@patterdalezipsuzilil]

😂 nothing do with drying cloths it's just general heat

[@orange1666]

Install a dehumidifier in the house , that will at least deal with the root of the problem

[@billdoodson4232]

I'm surprised that a roof as young as that appears to be, is on a listed building.

[@wotcherfaz]

Can't what you're saying in last minute or so...

[@thespecialist786]

What a waste of time

[@ricardopelc-wesoly3483]

Could you do a better job in explaining these issues or would you be wasting your time.