insulation ON floorboards..erm, help....

[fingerfun]

We have a large (8.5mx7m) attic in a detached 30s house with zero insulation. With the hot air rising and the cold weather, condensation is forming even though we have a draughty attic. This is causing loads of mould on the stuff stored up there... So we need to insulate and quickly.
The obvious thing is to insulate the floor of the attic BUT proper floorboards have been layed ages ago (even though it is only hatch access) - ie a right big, sorry HUGE, job to remove all of them.
So is it ok to lay some insulation over the floorbaords and what is the best kind? We only use it for storage so I don't mind an awkward-to-walk-on floor.. What are peoples thoughts?

Many thanks

 

[Deluks]

We have a large (8.5mx7m) attic in a detached 30s house with zero insulation. With the hot air rising and the cold weather, condensation is forming even though we have a draughty attic. This is causing loads of mould on the stuff stored up there... So we need to insulate and quickly.
The obvious thing is to insulate the floor of the attic BUT proper floorboards have been layed ages ago (even though it is only hatch access) - ie a right big, sorry HUGE, job to remove all of them.
So is it ok to lay some insulation over the floorbaords and what is the best kind? We only use it for storage so I don't mind an awkward-to-walk-on floor.. What are peoples thoughts?

Many thanks

How have the floorboards been fixed? If they are screwed (as they should have been) then a cordless drill/driver will have them up in no time. Alternatively a circ. saw set to a shallow depth of cut (ie: slightly less than the boards thickness) will make light work of getting them up. You may not be able to reuse them though.

Anyway, your question, standard rolls of insulation would do the trick. You might want to use spaceblanket or 'easy-lay' type. As this will have a covering to reduce itching from the fibres.

Alternatively use rigid board such as celotex/kingspan etc. should be walkable as long as you aren't wearing clumpy boots, plus you can store stuff on it. Xtratherm is a cheaper alternative, probably more suitable for what you're after.

 

[fingerfun]

Many thanks Deluks. The boards are nailed down and looking at the size of them I guess they were done at the time of building as getting them through the loft access hatch would have been a bit of a nightmare...
I have heard of Kingspan but wasn't sure as to if it would be strong enough to stand on. That Xtratherm looks perfect and not too expensive so I'll be ordering some of that!.
Many thanks again - will be using this rather excellent forum again!

 

[JohnD]

Condensation is caused by damp air.

Insulation does not stop damp air getting into your loft. It just makes the house warmer.

You need to find and address the causes.

If you are sure you have a good through=flow of ventilation (check that it has not been blocked) then you need to look at where the humidity is coming from.

Some possibilities:

- Hot water in the loft tanks due to pumping-over or other plumbing fault
- No cover on water tanks in loft
- Steam rising from bathroom due to not using an extractor fan during and after baths and showers
- Excessive humidity in house due to leaving wet washing about the house or draping it over radiators
- Bathroom ceiling cracked or gappy allowing steam to rise into loft (especially around holes for light fittings, pipe and switches)
- Incorrectly fitted bathroom ventilator or extractor venting into loft
- Badly fitting loft-hatch allowing excessive amounts of warm moist air to rise through gaps.
- Use of "condenser" tumble drier. Most of these allow a lot of water vapour to escape
- Use of vented tumble drier with no hose going outside; or faulty hose
- Use of paraffin heaters or gas fires that do not have a flue

Water vapour is lighter than air, so it rises through the house even more than warm air does. This is why clouds are above us.

 

[fingerfun]

Thanks JohnD. Interesting... hmm.
A new baby equals shed loads of washing and tumble drying plus hanging towels on radiators Might not be helping in combination with the weather... There's no hot water tank up there (combi boiler) so its not that...
Unfortunately we're not going to be able to stop the amount of dampness we are currently producing so I guess window opening is advisable, but surely insulation will keep some of the damp down?
Would a de-humidifer help at all? - problem is (in my eyes) as the attic is completely void of insulation (even in the roof of the house) it may well be like putting it outside; it'll always collect water without solving the problem!!

SO to date, I will be putting a layer of insulation down and increasing ventilation in the mainpart of the house. The attic is well ventilated so that's ok.
Any other thoughts from you wise folk?

 

[masona]

Would a de-humidifer help at all?

Up to a point it does but it blows out warm moisture back into the room!

Really need more air change in all rooms in the house at least once a day

Have a read here as what JohnD has mentioned

Another opton is the Drimaster which is a ventilation system to prevent and control condensation. I have no idea how much they are but do know someone who has them are very pleased with it and it make the whole house warmer.

I think I have seen them in Wickes(?)

 

[JohnD]

hanging towels on radiators

 

[masona]

Too big for my lounge, do they do smaller one?