Damp victorian living room

[Cherryburn]

I believe you actually lose a surprising amount of heat through your floors, especially if they're old and drafty. In terraced properties it can be a bigger source of heat loss than the walls. You also have to consider that a significant volume of moisture comes up from the subfloor and contributes to high humidity in the house, which itself has a big impact on heating costs. If you can limit that with insulation and appropriate membranes, you essentially get a double benefit. Just as long as there's adequate subfloor ventilation to clear the humidity on its own.

Floor insulation is pretty much a solved problem. It's disruptive, but we know what best practices are and that following them will result in a stable system. Wall insulation, on the other hand, is much more situational and there's a lot to consider with what you can do in any given house. There's a lot of different options, but there's often not options without any downsides or complications.

 

[alexander]

in reality you only lose a very small percentage of heat through your floor space but constant air flow to the floor joists will prevent rot in the timbers, you biggest loss is your loft & walls which account for about 70% of any heat loss in a house, although non breathable insulation on the walls will cause you problems long term wood fibre is ideal for walls as it still allows the walls to breathe.

what would you like to know why about, all wood products will dry out with ventilation if they get wet, they allow moisture to escape, modern foil board insulation does not it keeps moisture trapped in the structure causing especially in walls to become cold .which then allows condensation to form more easily, insulation works in both ways it keeps both hot and cold in so once you get a cold wall caused by trapped moisture the insulation keeps it cold, insulation does not heat up without air flow it creates problems long term, you cannot stop condensation happening without air flow & somewhere to allow moisture to escape to or a product like wood/ lime plaster/render that allows moisture to pass through.

 

[Cherryburn]

I can barely follow what you're saying, but foil board insulation isn't generally used in timber floors. Maybe newer builds, but they're mostly concrete floors anyway. Regs only call for a U value of 0.25 when refurbishing existing floors, which can easily be achieved by fully filling between the joists with mineral wool, woodfibre or sheep's wool. You manage moisture movement throughout the system with appropriate membranes. The key principle to stick to when insulating timber elements (whether it's a floor, wall or roof), is that you want to make it hard for water vapour to enter the system, but easy for water vapour to escape from the system. So, breathable membrane on the cold side of the insulation, vapour control layer on the warm side of the insulation. This is probably better explained here, though there are plenty of alternatives to the products they recommend.

Suspended Timber Floor Insulation: From Above Installation Guide (Method 1)

This step-by-step guide provides all the detail needed for a successful installation of underfloor insulation. Written as a follow up to our popular blog

www.ecologicalbuildingsystems.com

The only reason not to do it is if the subfloor hasn't been dug out much and filling between the joists would significantly affect airflow, or if doing so would prevent there from being a continuous path for the air to follow from one side of the building to another. Eg. over a dwarf wall, though you can work around that.

 

[Maria D]

I've been removing wallpaper room by room and one of the ground floor rooms appears to be insulated with some sort of wood fibre or chipboard. None of the other room have it but I'm afraid to pull it out in case I pull down all the plaster with it. Should I leave it? From what you are saying, it is probably breathable although I don't know that is is adhered with.

 

[larry]

Be

I've been removing wallpaper room by room and one of the ground floor rooms appears to be insulated with some sort of wood fibre or chipboard. None of the other room have it but I'm afraid to pull it out in case I pull down all the plaster with it. Should I leave it? From what you are saying, it is probably breathable although I don't know that is is adhered with.

View attachment 15106

I'd be interested to see what others thought and hard to tell from photo but what makes you think wood? It's about the right colour for brown (gypsum) plaster though.

 

[Stevers]

Maybe in Ireland they also used lath and plaster on some external walls, and this is a fibreboard/chipboard replacement.

My wife's uncle, panelled her mother's damp little cottage out with oiled hardboard on battens, (having strap pointed the outside in cement), so there's all sorts of stuff out there to be discovered - and potentially undone.