Do you need to ventilate your cavity walls?

Do you need to ventilate your cavity walls?
You need an airtight inner leaf, proper insulation, and adequate weep holes to allow water drainage from cavity trays and DPCs.
Cold bridging and damp potential if these details are not addressed .
#CavityVents #BuilderMistakes #AirtightConstruction #CavityInsulation #WeepHoles #CavityTrays #DPCs #ColdBridging #BuildingInspection

[tomoose]

Hi Jeremy, i wonder if you've seen skill builders latest video on this subject and could tell me your thoughts? I'm trying to make sure i've designed all of the details prior to my build but its proving very difficult. Happy new year. All the best.

[shadejalik]

ok well how do you vent the cavity? cos the only airbricks i've seen in my properties mostly have attached a 100mm plastic tube to the outside for a shower or to directly ventilate the inside of the house ... i've inspected some of these vents that are just airbricks without plastic tubing, but even they are slated off all the way on the inside so the air is just going directly into the living space and not into the cavity

[shadejalik]

doesn't make sense to me that airbricks would be of any use to vent a cavity when insulation is mean to block air flow for heat retention.. and given the fact every brick in the house absorb water and dry out, so they are self-ventilating building parts ... as long as they're not blocked from expelling moisture to the outside of the house by... insulation ;)

[kelvsOse]

Good day. Thank you for giving light to the heat insulation problem. I live in Nigeria, West Africa. I’m curious, what would work best for heat insulation in a climate like Nigeria? I’ve been researching on double cavity brick walls. However, I suspect that though the insulation will slow down the rate of heat absorption in the inner walls, the inner walls will retain the heat at night keeping the inside space warm. The issue is my climate is a hot one both day and night. What would work best for heat insulation and reflection to keep the inside space cool all day and night? I really do need an answer to this please?

[tomzeltmann]

If you have a flat cool roof with a composite roof (built in the 60’s)…what is the best way to add insulation?

[kingofthetrowel]

I’m a bricky and let me tell you the 10mm cavity is a load of tosh as you’ve said trying to maintain it whilst the snots squish out at the back even when a proper bed is scraped past makes it very difficult, always vent the cavity if you can

[adamuk]

Missing cavity trays seems to be common too 🤦‍♂️

[handle]

What size vents, do weep vents count? Would you close off the top of a partial fill cavity thats 150mm consisting off 100mm pir and 50mm air gap?

[christianvanderstap]

Either vent or no cavity if I remember correctly

[damdamdam]

All cavities should have a tray in and therefore has air vents, all be it small ones every two bricks…

[weeeeehhhhh]

What if it's rendered block instead of brick?

[darrenpodger]

Unless it's a solid wall no cavity

[tenforward]

This is wrong, note he does not explain why a cavity needs venting. A sealed cavity is vital to its function. Basic building science, this guy is an amateur pretending to be a professional.