Loft boarding vs loft insulation

[kissmekate]

Probably a really stupid question.... If I boarded my loft out with those MDF plank things would this give me enough insulation to not bother putting loft insulation down?
Any ideas/thoughts welcomed?

[tricky]

boarding the loft will add no insulating value at all. To achieve the current building regs you need 250mm of mineral wool insulation.

If your looking to do as much as you can AND have a boarded loft the fill between the ceiling joists with insulation then board over the top. If the boarding is not important, 250mm of insulation and loose the boards

[MisterT2]

There are a lot of grants etc around at the moment for insulation top-up. I will be putting in 4 by 2 on top of the ceiling joists and then reflooring. Advised to do this as this will reduce the pressure of squashing the insulation down which could pop the plasterboard below.

[shrek101]

I just boarded up my loft with the MDF stuff you get from B&Q. I just laid the old loft insulation between the joists admittedly I had to squash it down as I had rather a lot, only recently got done, Unsure what benefit I got other than can use some extra space for storage and kids play room (small loft)

[tricky]

I would be wary about putting any significant loading (i.e. 4"x2" 's) on the existing ceiling joists. Because these members are in tension, they are designed down to very small section sizes, and are usually only capable of taking the weight of the ceiling (and a bit of rubbish in the loft).

Before you add any significant loading, get your existing joists checked.

[Woby_Tide]

doesn't it depend on your house though as to whether it's just holding up ceilings etc.? I thought older houses especially(esp. those with brick interior walls) had joists etc. that could cope with a reasonable load?

[tricky]

Regardless of the age of the house, if the roof is made from rafters instead of trusses, it will more than likely have mid span loadbearing walls and!these will have been taken into account when designing the joists. The joists will only be designed to take a minimal load over the span they are designed for, whether it be between intermediate walls or the entire depth of the house.

Therefore the point in my previous post still stands. Unless specifically designed to take a floor load, always assume that ceiling joists in your loft cannot take additional load.

If you want to put any significant load in the loft, the least you should consider is laying new joists in between the existing. However, always take advice from an engineer first.

[speedyjoe]

, Unsure what benefit I got other than can use some extra space for storage and kids play room (small loft)

Don't mean to be heavy but think what might happen if there was a fire. Most lofts are accessed by a single hatch - difficult to to get the occupants out if the fire was to start in the region under the hatch :-(

Joe

[tricky]

According to the Building Regs, a loft can be used for storage only. As soon as it becomes a habital room i.e a bedroom or playroom etc, it needs to comply with Part B of the building regs which impose all sorts of restrictions, such as an enclosed staircase, fire doors, fire escape windows (depending on the situation) etc. On top of this you'll have to deal with the heat loss regs and ventilation regs which will mean you will have to insulate between and probably below the rafters.

As soon as you start using your loft for anything more than storing a few boxes.......it starts to become very expensive.

[shrek101]

Thats true about using other than storage. I know quiet a few people who use lofts for things other than storage. IE nextdoor users it for model railway, a mate uses it for computer room none have had planning permission.

Mine is used (still aint complete yet due to lack of funds) a play room for the kids. I cant afford doing it properly nor would it be worth it as you cant stand up in it. The kids got to play somewhere, we aint got the room in a small terraced and with no garden just a small backyard, pavements unsafe due to idiot drivers who su ethe pavements to drive on, playgrounds kids get bullied by yobs, what else is one suppose to do?

[hilstep2000]

I had boards in mine when I moved in and used it for stage, but recently have emptied it and got a grant for insulation... the house is sooo much warmer!

[alanobrien]

Probably a really stupid question.... If I boarded my loft out with those MDF plank things would this give me enough insulation to not bother putting loft insulation down?
Any ideas/thoughts welcomed?

No it wouldn't.
Its the air gap in the insualtion material that creates the insulating barrier not the thickness of the material.

I have heard of people putting 200 mm of insulation in a loft then compressing it down and boarding over it which is a waste of time and money.

Funny old world

[Ripperoo]

I have heard of people putting 200 mm of insulation in a loft then compressing it down and boarding over it which is a waste of time and money.

What about putting insulation material between the joists and boarding over the top (uncompressed of course) AND putting insulation material between the ratfters and boarding over them?

Would that be any good?

I urgently need some storage and was planning on boarding out the best part of the loft, but now it sounding like a bad idea (too bad I've already bought a heap of loft boards eh? )

[tricky]

It would be better to do just the latter of your two measures.

I would use a combination of rigid and mineral wool insulation. Say for example your rafters are 150mm deep. I would put 100mm mineral wool insualtion between the rafters and approx 50mm (depth depending on the type) rigid board insulation on the underside. Then a polythene vapour barrier then your plasterboard.

One thing you must do is maintain a 50mm air gap above the insulation AND make sure the air can get in it at the eaves. The only way to circumvent this is to remove your sarking felt and install a breathable membrane. However this would be a major job because you would have to entirely strip the roof.

You can then board out the loft and use it for storage (only) in the knowledge that the rubbish in the cardboard boxes wont rot cos its nice and warm.

Have a look at this site...

http://www.knaufinsulation.co.uk/out.../page_216.html

[cattie]

I had my loft insulated & fully boarded a few months ago. I was advised to go for an insulation by the name of Airtec double. It's thin, foil backed & equivalent to 55mm of polystyrene insulation. It's available from Screwfix.

It works out a bit more than conventional insulation, but saved me having to have battens on the joists to enable the required airflow, which of course I would have to have paid the guy to do anyway. So I think was cost effective on that point. It was quick, easy & clean for the guy to lay. He was able to lay it over the existing insulation, which was far from adequate anyway.

[tricky]

I dont think what you had done is the correct application, but anything is better than nothing i suppose......have a look at this......

http://www.ybsinsulation.com/airteccdryline.htm

[cattie]

Ooh, thanks for that Tricky, bloody expensive mistake I've made then. As this is what the carpenter recommended in preference to laying standard fibre insulation before he boarded the loft, I assumed he knew what he was talking about .

Is this going to be of any benefit to me at all insulation wise, or am I faced with the prospect of having to get someone to rip up all the loft boards & starting the whole job over again, but properly this time? It's already cost me over £800 to get done so far! Arggh. :'(

[tricky]

dont panic cattie......Although its not the use it was designed for, its still providing you with additional insulation. Further, if your criteria for the job was to:

board out the loft for storage only
not reduce the head room
upgrade the existing insulation
and
not add any significant loading to the existing joists...

then you would probably arrive at a solution similar to the one youve got.

If you want to use the loft for anything more than light storage, then you'd end up with a much bigger job

[eilz]

What about if you topped up the loft upto 250mm (recommended amount I belive) then put blocks on the ends to raise the original level and put the floor boards back on, this way you are not squashing the insulation. A friend of mine said I should think about putting a floor board with airholes in it, to help keep the rooms warmer?

[Mark Smith]

I recently did our loft out. I know there can be problems with permission of use but I have lots of friends who utilise their lofts and have not applied to building regs. Having said that, the building regulations are there for a reason and the safety of your home is hugely important. Especially if you use it for a kids playroom shrek101!

We decided to insulate our whole home to try to cut down on heating bills. We had some very dodgy advise too kissmekate! Just because someone is a 'builder' doesn't mean they know their stuff! You're best off with a registered company! It can be an expensive business if you go to the wrong place. We used The Mark Group. They have a scheme where you can apply for grant assisted insulation. We had our cavity walls done and it cut our costs dramatically. I wouldn't like to say how much as it was a year or so ago but our friends used them more recently and managed to get funding with their project too! Worth a look!