Loft insulation

Fair enough - What about the ventilaition issue though? My loft curently is fairly sealed so I'm intending to fit ventilated soffits (in the future) and not insulate to the very edge etc. Is boarding laid directly over insulation with very little air gap likely to lead to problems (condensation etc) later? If I lay less insulation to give an air gap then I will lose any insulation properties that the boards give as the air will no longer be trapped?

I don't really want to go the whole hog of laying plastic sheet (as a vapour barrier) if I can avoid it hence my thought that the greatest amount of 'damp' air is in the bathroom so I won't boasrd over that...

Thanks for the advice so far...

Peter

Reply to
Peter Watson
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Thanks - your explanation has made things a lot easier (and cheaper). Cheers!

D
Reply to
David Hearn

If your bathroom has a window or a fan extraction system, then why worry about damp air escaping through the plasterboard ceiling ? You can insulate and board over the whole area in the loft of you want, unless that is, you have holes up through the bathroom ceiling into the loft space.

No one is stopping the ventilation into the loft, you're only lagging the space directly above the room ceilings to trap air so it doesn't escape as quickly as it otherwise would. If that makes sense. :-))

Reply to
BigWallop

Blockboard and chipboard are two very different materials

I'll have to check a spec sheet, but i am pretty sure that decent t&g chipboard is manufactured such that once the tongues and grooves have an adequate glueline and butted up they don't *need* to be over a joist, but for the cautious person a few noggins help.

What you can do is ask at your local timber merchant for a spec sheet, most packs of chipboards, i know vertex did which i think went on to be reynolds and now kronospan has several sheets wrapped up in each pack of 72 has nice diagrams of suggested laying methods

Reply to
David Hemmings

Hi Folks,

I'm probably too cautious but I always make sure that any joint is supported with a noggin if it doesn't always work out to be over a joist. True, the chances of someone jumping up and down on it are slim, until my 15 year old lad ran along our upstairs corridor and jumped and landed on a joint with such force that he broke the tongue&groove! He then reported the fact that "the carpet gave way" which I always find amusing!

Simplifying for ascii-art, the tongue is like a "TTT>" and the groove like a ">GGG". With any downward pressure the weight must be on the lower edge of the groove's ">" ? Therefore half the wood thickness is supporting the 15 year old landing on it... snap.

If you are going to board an area for walking on, methinks it won't be that much extra effort to put (say) four by two noggings to support some part of a tongue and groove joint. If it were to snap, consider how far the person may fall when they slip down through the crumbling plasterboard. In my house the worst drop would be through the ceiling above the stairwell... about 3 metres.

Just my opinion.

Mungo

Reply to
Mungo Henning

You mean that every builder and joiner using the chipboard flooring in new builds, has to put dwangs (noggins to you southerners) on the edge of each and every board they lay and fix. I think you should get on to new building sites a bit more. :-))

Reply to
BigWallop

"Southerner" indeed ... I'm from Ayrshire! :-)

What happens in "new builds" is not my concern. Squeaky floors and

15-year-old kids dislodging chipboard flooring IS my concern, but only in my house.

Having replaced the floor of a friend's porch we had one extra 8' by 2' length of flooring grade chipboard left over. I suggested to the friend that they install the surplus board in their loft - they might as well use it somewhere. The plan was to take the hand circular saw and cut the board so that each half would be easier to fit through the loft hatch. "Ah but no" says I "I'll need to see the spacing so that the end of the board sits on top of a joist. "But I haven't done that" says the householder. As it turns out the sparse boards that the householder did install were nailed down. Imagine a 13-stone bloke standing on the overhang of such a board, relying on the nails to hold it down!

So the final decision was that I could keep the surplus board myself.

Mungo

Reply to
Mungo Henning

Now that is asking for trouble. :-)) I said, only if the other boards around it were fitted into the tongue and groove of the other boards. That way, any overhangs are left out at the edges which you can't stand on. But the design of these boards is meant to take the weight of normal use on the tongue and groove sections.

Reply to
BigWallop

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