Possibly looking at flooring my dad's loft for storage - he previously had old doors etc randomly spread over the joists with stuff sitting on them.
However last year he got his loft re-insulated and the insulation is all much higher than the joists.
Now doing some googling the options seem to be
- adding timber to the existing joists to raise them up enough to lay boards
- buying loft leg extenders which seem to be some sort of plastic feet that you screw into the existing joists to then give you more height for the loft boards
- don't do it due to potential dampness, condensation
- don't add more weight as it will bring down your ceilings
- professional job with all sorts of structural issues
I have laid boards before straight onto joists, but has anyone done this after having extra high insulation installed?
If so, what method did you use?
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Take out the expanded glass insulation and insert insulation boards such as Kingspan between the joists (100mm is enough) and then floor the joists.
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Too expensive and messy am afraid - the loft insulation was done for nothing.
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>> Too expensive and messy am afraid - the loft insulation was done for nothing.
you get what you pay for.
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Only if you have the money in the first instance
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For the part of the loft that I use for storage, I laid kingspan boards across the joists and over the rockwool insulation between the joists. Then laid boards over the kingspan. But my rockwool doesn't come above the joists very much so only slight compression. Looks like you need the joist extenders.
I don't have heavy stuff up there, so the kingspan is strong enough.
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>> Only if you have the money in the first instance
Very true, you need to save it for a very much more expensive loft boarding solution later.
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>>Very true, you need to save it for a very much more expensive loft boarding solution later
My dad's 82, I am sure this loft reflooring will outlive him
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>> Too expensive and messy am afraid - the loft insulation was done for nothing.
>>
Lots of cheap s/h insulation around I bought 6 full size insulation boards 50mm thick - used but good and emminently serviceable for £11 on ebay.
That's just over 6x(2.4x1.4) sq meters 20sq meters for 55p/sq meter.
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I prefer the Anglicised version MD !
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If you tell us what sort of insulation it is, what the installed thickness of the insulation is, and what the depth of the joist is, we'll have a better appreciation of the problem.
Last edited by: L'escargot on Thu 1 Aug 13 at 13:17
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Last year I fitted extra insulation in my loft. The rockwool now sits proud of the joists.
It gave me a good excuse to have a good clear out and remove the tongue and groove boards and bits of old wardrobe I had previously used.
I left a small area in the middle of the loft floor still boarded. It contains the header tanks etc and enough heat rises from the rooms below to avoid frozen pipes. The boarding also sits above the internal walls of the house so it should be the strongest part of the loft floor and adequate for what little storage I now need.
I considered raising the boards so that I could still insulate beneath them but went instead for the aforementioned clear-out option.
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Since you say *RE* insulated, did they just put the new insulation on top of the old? If so, perhaps you could take out the old to lower the level. It seems very surprising that it should be *SO* high.
As for dampness, just don't cover the whole floor. Leave gaps, especially around the edges. Also, if you have damp issues, don;t put boxes straight on to the boards; put pieces of wood or similar to allow air to circulate.
For the additional weight, then don't even think about storing weight up there if you have doubts, it could be catastrophic. I;d be a little surprised if there was an issue, but you need to be sure.
"professional job with all sorts of structural issues" - the structural issues will be there or not irrespective of whether you use a professional or bodge it yourself. What you mean is that a non-professional job can ignore them.
That may be appropriate/safe since the structural issues may be lowest common denominator regulation driven rather than actual safety driven, but you should quantify the risk, not just blast on regardless. Perhaps the neighbours have done something similar on a similarly constructed house?
I've never used extenders so have no comment on them.
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I'm 3/4 through this process but it is too hot up there now.
I have standard 100m (4") fibreglass insulation between the joists. I've topped up with Wickes 170mm insulation. For my boards I've used these:
www.toolstation.com/shop/Access%20&%20Storage/Loft%20Ladders/Loft%20Flooring%20Legs/d110/sd3303/p44016
I've used 18mm tounge and groove chipboard flooring but its heavy and a size to manouvre up through the hatch and then around all the truss braces. You can use specific loft boarding which comes in smaller pieces.
I've had to manufacture a deeper loft hatch to take the extra height as the boarding and insulation will come right up to it.
As for extra weight. Roofs are generally built to withstand weight and I have sufficient internal structure to support all the ceiling.
Damp shouldn't be an issue providing the loft space is ventilated and you are not letting warm damp air into the loft space. The lofty hatch should also be well insulated. I'm going to use Kingspan for that.
It is quite a time consuming ongoing project due to the size and amount of carp up there. + some of my ceiling joists are 100mm and some 125mm so I have had to screw pieces of 100mm to the 125 mm to keep everything level.
When its done I could get a massive model railway up there - but maybe not :)
You may also need to consider pipes tanks and extra frost protection leaving space under any tank you may have for warm to rise.
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>> I'm 3/4 through this process but it is too hot up there now.
> Good Lord, thats a lot of effort, is it worth it?
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I keep asking myself the same thing. It will produce lots of storage space to hold all the carp that Mrs FC seems very reluctant to sort through and have a good clear out.
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Fullchat, thanks for the info - do those extender things feel solid once they are installed and boards on them? They just look, kind of flimsy, that I could see the whole lot collapsing in a sideward motion.
Would you feel confident about walking on the boards on top of the extenders?
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The legs and chipboard have supported my weight and feel solid. The legs themselves are quite robust. You would really need some lateral force to start any movement and most forces you put on them will be vertical.
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Fullchat , quick question, these loft legs, presumably they go in the corners where the boards butt up together - can 4 boards be screwed into them or will they only maybe take two boards?
Or do you actually need to use 1 per board
ie a board stretches over 3 joists and runs at right angles to the joist. So on the third joist you will have one board stopping and the next starting. Can these bothe be screwed itnot he one leg?
Also at each of their corners will be the next board, so effectively 4 corners meeting together - can they all fit onto the one leg?
Hope I am explaining that ok........
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Ideally you should be staggering the boards so on one side you have two boards joining with a support underneath and then a complete board on the next row crossing the joint so the support is supporting three boards. Dont forget that the boards are tounge and grooved so they have their own strength on the joint and dont necessarily require a support under the joint. Infact I would think you would be lucky to have each joint directly over a support.
So looking at the job horizontally each row of legs is supporting two rows of boards. Of course you could position the legs in pairs so there are two legs under each row but I think that is overkill and would add to the cost of the job.
As I used the 2.4M lengths of board I didn't have the same issue but can understand your concerns. Have a dry run with a few boards and supports first. There are some youtube cllips covering loft boarding showing installation to maybe give you an idea.
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Cheers for that Fullchat, one of the problems I have is that if my calculations are correct, there are 5 joists so two of the standard loft panels will fit end to end, meeting on the third joist. So each panel will touch 3 joists.
I was planning on just doing these as rows out from here then, so it is going to be 6 panels wide and the 2 panels long.
I know its normal practice to stagger things like this but to do so, will result in a lot of cutting and at the end of the day, each panel is going to be on the same amount of legs anyway?
I nipped into Wickes tonight to look at the legs (was on my bike so couldn't buy them), I think each leg would take two boards but certainly not four.
As you say, will buy some and have a try at it. Thanks for the info .
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>> Also, if you have damp issues, ...............
Or problems.
;-)
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>>Since you say *RE* insulated, did they just put the new insulation on top of the old
Not sure if they took out the old first but I do know that this latest round of free insulation grants were putting insulation in that was much deeper than standard joist heights. I will go up his loft over the weekend to find out the exact heights.
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>> I have laid boards before straight onto joists, but has anyone done this after having
>> extra high insulation installed?
>>
>> If so, what method did you use?
In my 1930s house I had previously laid 8'x2' boards on the 4" joists with 100mm of insulation.
A couple of years ago, when the energy companies were heavily subsidising it at B&Q, I bought plenty of rolls of 200mm insulation to increase the total depth of insulation to 300mm.
I looked at the plastic feet but they were expensive and rather restrictive on positioning. So I devised my own system using 150mm timber feet supporting 50x50 horizontal timbers, with the 8'x2' boards re-laid on top.
The timber feet were 75mm lengths cut from some 150x50 joists I had, and screwed diagonally into the joists. The 50x50s were cut down from the same 150x50 joists and screwed to the top of the feet.
I fixed the new 50x50 supports across the joists so I could control the spacing to match the insulation and the boards (and to get vertical and lateral support from the binder/trimmer timbers).
Obviously with your insulation already there you will need to dig a bit to find the joists.
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What's the insulation value of 100mm Rockwall between the joists with chipboard flooring sheets screwed down to the joists?
If I brought my insulation up to 300mm I'd make my loft almost unusable. I've only about 1500mm (5 foot) to the ridge already.
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I have no attic in the current abode (jam packed with insulation) - I had to get rid of a lot of stored stuff. Cheap that.
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>> What's the insulation value of 100mm Rockwall between the joists
>> If I brought my insulation up to 300mm I'd make my loft almost unusable.
It depends how much you want your heating bills reduced. Take it up to 300mm and you will notice a difference. It's been said before but it's one of the cheapest things you can do to retain heat for longer.
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I have scrolled down to the bottom now without reading any more. I am between 50 and 60 YO. Married for 33 years. We had junk. We have junk. We stored it everywhere. We store it everywhere and then we 'get it down' and go through it and then throw it away. It is all an expensive exercise which indeed is expensive and nothing more.
CHUCK IT OUT..........................................NOW.
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Totally agree MD
If there is anything in your loft space apart from the water tank then you put it there to forget about it. YOU WILL NEVER USE IT.
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That's what I discovered. I kept my Science Fiction book collection, my Motorcycle Sport magazines going back to 1980. More or less everything else went, recycling, charity but went it did.
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Clearing an elderly relatives house after their death cures you of hoarding "Stuff". You can't take it with you and it will only end up in a skip.
Downsizing is another good method of clearing junk, if you can find someone who can afford your house. :-)
Last edited by: Old Navy on Thu 1 Aug 13 at 21:00
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Ah but....................................
If you keep a load of old rubbish up in your loft and then your neighbour sets fire to your house, you get to claim cash for every item that was up there!!!!!!!
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>> If there is anything in your loft space apart from the water tank then you
>> put it there to forget about it. YOU WILL NEVER USE IT.
>>
Not strictly true. We keep our Christmas decorations up there, and they get used at least once a year.
(As for the rest of the carp, though, you are right).
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Crocks, what you describe is one of the thoughts that I had - basically buying some timber and cutting it into blocks to support the weight, but these loft extender thingies are basically supposed to do the same job but to me they just look a bit too flimsy as in
www.youtube.com/watch?v=hrnIndaiPB8
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Yes CG, that system looks good but is £408 for a 4.8x4.8m kit without the boards.
What I constructed uses the same layout and spacing but is entirely timber. I used timber I already had and some old 4x2 rafters from my neighbour's skip during his loft conversion. So it only cost me my time.
If I had to do it again and had lots of money then I would consider that Loftzone system.
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I'd be looking at it from the other direction.
Until last year there was no insulation. Fuel bills were X.
Now insulation is in, fuel bills will be reduced - but by how much? Even the most optimistic completely made up figures from loft insulation companies talk about "up to" a couple of hundred quid. I'd be thinking that in reality it's about a tenner a year (which in fact is borne out by my own experiences). Not more than a few tens anyway.
For that money saving, it's not worth fiddling about. Reduce the insulation to match the joist height, board easily with no extra expense on gadgets and adjustments, and you'll still have some insulation, being better off than last year but with storage.
So you might end up saving only five quid a year over ten (or twenty five over fifty, whatever).
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Erm... I might be missing something but if it's rockwool (vile stuff) then can't you just put boards on top and squish it down a bit?
I've done this in my house where the insulation normally stands about three inches proud of the joists.
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>> Erm... I might be missing something but if it's rockwool (vile stuff) then can't you
>> just put boards on top and squish it down a bit?
>>
>> I've done this in my house where the insulation normally stands about three inches proud
>> of the joists.
>>
That reduces the insulation value, but assuming that only a relatively small percentage of the ceiling is being boarded it probably doesn't matter too much.
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Crocks, re your timber method, I would be looking just to use the standard loft flooring panels you get in any of these DIY places, think they measure 1220 x 300.
So each board effectively straddles 3 joists that are 600 apart.
I am thinking of buying a couple of lengths of thick wood to match the joist width and cut then in 175mm sizes. But instead of then doing a frame on these like you did, I would plan just to put the board straight onto them. So each board would be supported at 6 points as it meets the 3 joists.
You said that you just diagonally drilled screws into your timber extenders straight through to the joist - do these feel solid enough? I was thinking of maybe a metal bracket running flush up the side, screwed into the existing joist and the new extender? Or is that just overkill?
Incidentally, don't know if it is just sheer laziness or a deliberate tactic, but the guys who laid the insulation laid it at right angles to the joists, so basically up and over every joist. I suppose that way the joist takes a bit of the weight of the insulation but its going to make this a bit more of a messy job!
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>> Crocks, re your timber method, I would be looking just to use the standard loft
>> flooring panels you get in any of these DIY places, think they measure 1220 x300
>> So each board effectively straddles 3 joists that are 600 apart.
If your joist centres suit the smaller boards then give it a go.
I used 8'x2' boards because they are cheaper and I could get them through the hatch. But they are heavy beasts to transport and get up into the loft.
>> I am thinking of buying a couple of lengths of thick wood to match the
>> joist width and cut then in 175mm sizes. But instead of then doing a frame
>> on these like you did, I would plan just to put the board straight onto
>> them. So each board would be supported at 6 points as it meets the 3
>> joists.
My usual method with jobs like this is to "suck it and see". Give it a go in a sample area and see how it goes.
>> You said that you just diagonally drilled screws into your timber extenders straight through
>> to the joist - do these feel solid enough? I was thinking of maybe a metal
>> bracket running flush up the side, screwed into the existing joist and the new extender?
>> Or is that just overkill?
Two screws into each leg were enough for me. Since your legs will be free standing, if small legs wobble, then maybe use 100mm wide legs and drill in two screws from each side.
>> Incidentally, don't know if it is just sheer laziness or a deliberate tactic, but the
>> guys who laid the insulation laid it at right angles to the joists, so basically
>> up and over every joist. I suppose that way the joist takes a bit of
>> the weight of the insulation but its going to make this a bit more of
>> a messy job!
They probably just do it the quickest way they can. I doubt they are paid much per house.
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>> I suppose that way the joist takes a bit of the weight of the insulation
What weight? It's either laziness or speed. If the joist can take someone's weight or storing things.... it's not going to be an issue having insulation resting on it.
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I think you'll find that's the recommended way of laying insulation.
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The flooring loft in this house was constructed with paper mache, glue and staples
tinyurl.com/kpay6bv
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Flooring loft for storage - madf
