boarding a loft

[velosam]

So in theory I am back on the housing market, as long as the whole purchasing process goes OK.

However, the prospective new residence does not have any boarding the loft (but has light!).

I seem to have accumulated loads of chipboard (dismantled cupboards) - is there any reason I cannot just put these on the joists?
The loft space will be used to store suitcases and packing boxes.

thanks

[Kim]

Insulation?

[spesh]

Insulation?

I used loft flooring legs/stilts to raise the boards up when I was topping up the insulation in my loft:

https://www.toolstation.com/shop/Heating+%26+Insulation/d230/Insulation/sd2738/Loft+Flooring+Legs/p44016

[Blodwyn Pig]

I would suggest that 'chipboard' from wardrobes, would be fine for storing boxes on, but should you ever need to walk on them to retrieve boxes 'at the back' you might well put your foot through it and make a hole in your ceiling.  Its not really strong enough to walk on. eg older terraced houses sometimes have the ceiling joist c/cs around 380mm but a modern house , say with a trussed roof, might have the joists at 600 mm c/c. Id say board it properly, with interlocking t+g boarding,, then you are 'free to roam'  (unlike in Europe next year apparently  )

[velosam]

cheers. It has insulation just no boarding.

I may just get the proper stuff and put it on

thanks

[T42]

22mm chipboard is the stuff they use over here.

[tiermat]

Wickes do packs of Loft Boarding, works out about £7psm, but well worth it.  From memory it's 18mm, which is good for 50kg/sqm.  That is good enough for occasionally walking over (as in not using the space as an office/work space) and for storing "light" items (no safes, weight training sets or anvils).

I have just recently done ours, and spent $notalot to get it to a point that we can use it (previous owners just laid boards over the top of the second layer of insulation!)

[Kim]

... 50kg/sqm.

Just remember: when you take a step you are, for a moment, putting all your weight on one foot, way less space than a square metre.

It's worse than that, you're accelerating upwards.

[LittleWheelsandBig]

Generally that sort of 'point load' isn't a major problem, given it is designed to support quite a large loading over the entire area, provided you don't punch through by wearing stilettos.

[Kim]

Or more realistically, pivot that filing cabinet around on one corner.


Last time I had anything to do with a boarded loft, some strategic plywood was placed on top of the chipboard to accommodate heavy objects.  Sorted.

[Aunt Maud]

I'd be wary of using chipboard for anything other than filling up a skip.

[Jurek]

I'd be wary of using chipboard for anything other than filling up a skip.

Word.

[velosam]

I thought the stuff was ok as it has been holding a load of crap in the cupboards - but I guess it’s doesnt weigh over 75kg!y

[Brucey]

a long time ago I boarded out my loft; I added 3" to the joist height (which made them at least twice as stiff), added noggings to brace the new deep joists (which were on about 14" centres or something), and used tongue and groove floorboards to cover the surface. Not the cheapest or quickest way of doing it, but the resultant floor is probably able to take about one tonne per square metre.

Chipboard is alright for a little light storage, but it is only just good enough even for that.

cheers

[Aunt Maud]

Velosam, Chipboard suffers badly from creep and has very little abrasion resistance.

Another reason why I don't like it in a house, is that it is a composite full of adhesive. It also gives off very toxic fumes when burnt, so it just doesn't meet my criteria for a material suitable for a dwelling.

[Frank9755]

When I moved to current house in 2001 we had builders in. I got them to put boards in the loft. They used tounge and groove chipboard, I don't know how thick but surprised if it's more than 2cm.
It's been fine for the last 17 years. Has held my weight when I've ventured up there, plus the various boxes stored on it. Nothing too heavy, normal loft junk.

[Dave_C]

We have the centre of our loft boarded with old wardrobe doors and sides. I have lots of small stuff up there like suitcases, boxes storing sleeping bags and camping stuff etc.. Never had a problem going through any boards. The joists are the usual 4 inch jobs not the std 6 inch flooring. My other half's mother had her loft converted and the builder (working to the structural engineers spec - post Architect's plans) just doubles up the joists and roof supports and screwed them in, in effect doubling the width of the joists.

I like the idea of those legs raising up the boards to allow more insulation, as our central section has only 4 inches/100mm of old stuff.

[Whitestone]

A few years ago when I was "between jobs" I sorted our loft out. Previously the "boards" were just whatever had been left over from when the previous owner had built an extension and were just lying across the joists, not nailed/screwed down and loads of traps

The joists were only 3" deep (this is the old section of the house) and the insulation had seen better days and was probably only 30mm deep so I got rid of that and screwed 25mm roofing batten on top of the joists, put new insulation in and then used flooring panels. They were 2400mm x 600mm and probably 18mm thick. The joists were at roughly 400mm centres so didn't need ultra thick panels, if they'd been further apart then I'd have fitted thicker units. I didn't use T&G as there's a lot of cabling up there so having simple tacked down boards lets me get to them should I need to. Using the battens meant that the screws I used to fix the panels wouldn't accidentally go into the cabling.

I wasn't rushing and the whole job probably took me three days with going up and down to do the cutting outside then taking the panels up the (new) loft ladder.

[LEE]

The term "Chipboard" covers a variety of materials.  Use Tongue and Groove flooring boards from any DIY store.  It's very cheap and designed for flooring loads (It's basically structural chipboard).  The T&G distributes the load better than butted joints.
Always remember that you're walking on ceiling joists, not floor joists, so try to store things around the edge of the roof or where the joists run over structural internal walls.

Whitestone (above) did the right thing and stitched-in some extra depth to the ceiling joists.

What age is the property?  Modern roof construction can be designed to the absolute minimum when compared to, say, 1950s properties. 

It's no use listening to "It worked in my roof" anecdotes.  Nobody else has your roof.

Note. When I had an extension built I specced floor joists in the loft rather than ceiling joists like the original house.  The difference in thickness made me worry about the integrity of my existing boarded loft.

[Diver300]

It's no use listening to "It worked in my roof" anecdotes.  Nobody else has your roof.

One house I saw had been converted from a medium-rise block of flats. I had been cut down to two floors, and then a tiled roof added.

The upstairs ceiling / bottom of the loft was the old floor of the former 2^nd floor flat, so was 100 mm of reinforced concrete.

I don't think that there was any need to board it to spread the load.

[Brucey]

....Whitestone (above) did the right thing and stitched-in some extra depth to the ceiling joists....

It gives you more depth for insulation but in addition it increases both strength and stiffness.

The increases in strength and stiffness that can be acheived this way are remarkable; just adding 1" to a 3" joist as per whitestone's description means the joists could be ~x2.37 improved in both strength and stiffness.

 When I increased (approximately doubled) the depth of my joists they became nearly x8 stiffer and x8 stronger.  In fact it was better than that because the noggings transfer local loading better to neighbouring joists than the original arrangement (a cross-nailed spreader timber over the top of the joists at right angles).

 Just for fun  I had an assistant measure the ceiling deflection in the rooms below under my bodyweight. It has been awhile but IIRC it was roughly;

a) original ceiling joists, with cross-nailed spreader in place; static bodyweight caused 3/8" deflection, flexing ones knees gently produced over 1/2" deflection.

b) improved joists, with noggings. Maybe 1/16" deflection static, 1/8" by flexing knees.

c) original joists with spreader removed; 3/4" static deflection. Flexing one's knees caused well over 1" deflection and loud cries of 'please stop it looks like you are going to come through" from below....

cheers

[MikeFromLFE]

Similar to Wheatstone, what I did was to buy spacers that billed on top of the dusting joists, giving more room for insulation, then used B&Q roofing chipboard (t&g) screwed onto these supports. In places there is old carpet laid over the new "floor" which may add a bit of extra insulation and might reduce the load on the joints.
It took me about 5 sweaty days of working slowly to do the work.

[Aunt Maud]

Noggins give the floor rigidity by preventing the joists from rotating or buckling under load.

Traditionally this was provided by nailed on herringbone strutting, but it's less labour intensive to to screw a single piece of timber than make a herringbone strut and is the reason solid noggins are now used in modern construction.

They shouldn't be relied on to increase the floors ability to carry greater load, that's the job of the joist not the noggin.

[thing1]

Or you can use these to raise the boards above the extra insulation height, and concentrate all the weight in a few discrete places on the underlying joists



https://www.diy.com/departments/diall-loft-storage-stilt-pack-of-12/181925_BQ.prd

[MikeFromLFE]

Yes, that's what I was describing. I used twice as many as recommended.