Next project in the moneypit is to improve the loft access, storage and insulation.

Looking for ideas and recommendations for:
1. Decent loft ladder that’s easy to fit DIY?
2. What should I use for boarding out the loft, currently there are old bits of wardrobe up there on top of the rafters for storage?
3. What insulation, it has a reasonable depth of proper horrible old fiberglass wool stuff?

I was thinking of trying some of those loft stilts and then putting chipboard with some sort of solid insulation such as kingspan on top of the existing stuff as it would be a nightmare to remove it all.

Suggestions?

following with interest.
the loft stilts look expensive.

I did the following:

1. Insulate with rockwool to depth of existing joists
2. Fit new joists on top at 90 degrees.
3. Insulate with rockwool to depth of new joists
4. Screw loft boards over the top.

Remember to route any wiring over rather than under the insulation.

loft stilts and then putting chipboard with some sort of solid insulation such as kingspan on top of the existing stuff

Isn’t the idea of the loft stilts to allow you to use the normal rolls of insulation rather than solid (more expensive and awkward to get into a loft) Kingspan?

Also remember that a lot of ceilings joists are only 4 x 2 if you’re lucky so don’t go banging shit loads of weight up there with “extra joists and heavy flooring”…

wrightyson – Member
Also remember that a lot of ceilings joists are only 4 x 2 if you’re lucky so don’t go banging shit loads of weight up there with “extra joists and heavy flooring”…

this was my original idea and then thought.

this was my original idea and then thought.

My thinking was that the extra timbers don’t weigh very much, and spread the load much better over the existing structure. Anyway, it’s been there for over ten years…

The loft stilts did look expensive for what they are…might be cheaper going with extra joists. I’m sure they could be fashioned to be able to provide support as well?

I’m not looking to put loads of weight up there, mostly boxes for stuff. But do want it to be good enough to walk around

Re. wires over stuff, they currently are buried…these are lighting wires – and been like this for a long time. Is this a fire risk then? I would have thought the current they carry is minimal?

Re. wires over stuff, they currently are buried…these are lighting wires – and been like this for a long time. Is this a fire risk then? I would have thought the current they carry is minimal?

Lighting shouldn’t be a problem – I was more thinking of a shower or mains circuit. But practically, it’s easier if you know where the cables are (say if you wanted to reposition a light pendant) than if they’re all buried. The other thing I had to do was cut holes in the insulation above the ceiling-mounted halogen lights in the bathroom. LEDs & fire-rated fittings should solve the problem I would think.

I’m going to say something against the grain here.

If you use a PIR board (Kingspan etc) on top of rafters, do not fill the joist voids as you will trap moisture and the rafters will rot. I’ve been speaking to a lot of builder types recently about this, and though it hurts my head to accept it, it’s generally considered a bad thing.

Best bet, is PIR board on rafter and then T&G chip board flooring bolted directly through the Chip and PIR to the rafters. The PIR will not compress as it has very good load baring especially with a board on top.

That said, it’s hard to get a PIR board into the loft and into all the nooks and cranies, so may be best bet to fill the joists, but use a vapour barrier over the rafters before you put a board down.

Sui – so remove the old insulation, leaving a void, then pir across the joists, chipboard and screw the lot?

PIR on its own with a void under won’t give you a very good u-value if it’s extra insulation you are looking for. Two layers of glass wool not compressed will be much better. Stilts or extra joists at 90 degrees to the current ones will do that job. As for moisture damaging the timber, that shouldn’t be an issue if your loft is ventilated sufficiently and not a problem in the timbers covered by the insulation as it will be well above dew point.

Extra ventilation in the loft is always recommended when you add additional insulation as you’ll have lowered the temperature in the loft therefore increased the risk of condensation on the underside of the roof covering.

Use an architect?

Got Abru loft ladders here and so does the mother in law. Can’t complain about them.

Where are you located, OP?

If you use a PIR board (Kingspan etc) on top of rafters, do not fill the joist voids as you will trap moisture and the rafters will rot. I’ve been speaking to a lot of builder types recently about this, and though it hurts my head to accept it, it’s generally considered a bad thing.

I think that may be interstitial condensation?

I have seen it a few times on ground floor bathrooms that i have stripped out, where the gaps between the joists have been filled with kingspan. Bad move, the joists should be covered from below with KS also. Still wouldn’t recommend using KS under floors and in lofts.

The tops of the joists were condensating due to the cold air hitting the bottom of the joist and travelling up through it hitting the warm floor. No airflow at the top end of the joist due to the KS being tight between and level with the top of the joist means that the condensating joist doesn’t dry.

I would always recommend glass wool in lofts and under ground floors if retro fitting.

Oh, and one of the bathrooms i had stripped out with condensating joists was
spec’d by an architect, who wouldn’t believe what i was telling her about what was happening. She must have googled it at night as she was agreeing with me by the next morning.

Use wood fibre batt insulation – it will take in any excess moisture and release it again when the environment allows. No irritation involved with laying it and better thermal conductivity. We don’t use enough natural fibre over here.

Thanks Sui and supreme. Watching this with interest. Will go the 4×2 or stilt route with extra rock wool.

Can’t say the stilts appeal but I don’t want to load the ceiling.

I’m based in Southampton. Seems general consensus is stick to wool stuff then. Does it matter if I seal it over with chipboard on stilts (or batons)

I have a similar challenge. I suspect that just boosting the insulation at loft floor level will still leave me with condensation in the loft so I want to go for a warm(ish) loft. I’m planning to top up between the joists with rockwool, then board over it, then fix Kingspan between the rafters with a 50mm gap above it. I’ll also change the airflow at the soffit boards to seal the attic space and allow ventilation over the Kingspan. I’ve yet to sort out the details, do the dewpoint calcs, and check Building Regs; I may need a vapour barrier and ridge vents.

Go for additional joists at 90 or stilts. Ensure your eaves are vented (if they already are) and blow in the cellulose insulation. Easy to do, no irritation, more effective than rockwool. Rigid insulation in the attic is bonkers and far more expensive than it needs to be effective in that role.

I went for stilts, they seem expensive but at the time I priced them up against extra joists and they suddenly price up very attractively. Mine were designed for 600mm joist centres I think, my joists are at 400mm centres so the instructions would have you use more to board the same area. I fitted mine so they are arranged along the joists like the the no.5 side of a dice (i.e. offset) as this increases the span between the stilts towards 600mm (diagonally) rather than 400mm and avoided the need for a 3rd box 🙂

Even if the stilts work out more expensive, factor in the difference in effort compared to chucking two light boxes of stilts, a drill driver, tape measure and a box of self tappers through the loft hatch, versus collecting timbers, cutting them up, getting the things into the loft (factoring in small hallways, limited headroom above the loft hatch, existing rafter ties) and then you still need to screw them into the existing joists.

Also the stilts are often 175mm high which is a big old chunk of timber to achieve the same space for insulation.

Those worried about over loading the loft – there is a sodding great water tank in mine, so pretty sure it can take it, spreading the load on extra joists an that – the bitch of a job was getting right into the eaves and clearing out the overflow of cavity wall insulation that was blocking a lot of the eaves vents

I did ours a few years ago. It’s an old build and the joists were 3×2 so put 2×2 battens on top of these – the joists are supported by a stud wall down the centre of the floor below. Removed the old insulation – it had compressed and mice had messed about in it – new rockwool insulation then 2400x600mm fibreboard boards.

The local builder’s merchant had Fakro loft ladders so went with one of those, several models one of which should suit.

I used the loft stilts, main reason for me was that the attic had already been double insulated and battening the existing joists would have been a total pain. Once the first 2 rows are set the rest are pretty easy to install.

Oh, and if you’re moving old insulation about, it’s a filthy job. Buy goggles, gloves, mask and a paper suit.

Loft ladder. Get a wooden one. Being able to climb up in socks should not be undetestimated….

Re old compacted insulation, do I have to remove it? Or can I just roll new stuff over the top? Removing the old is going to be a bastard of a job.

Those using stilts were did you get them from? Amazon seems to do some cheaper ones than Screwfix

@stevemuzzy – the Fakro loft ladders have wooden stiles and rungs.

I’d remove the old insulation, even compacted it’s taking up some of the volume that should otherwise be used by the new insulation.

I did joists last time, stilts this time. They price up pretty similarly (especially over a larger area), but the stilts are much easier to get up there and fit (my old house had a larger continuous void without rafters). They also allow more airflow around the insulation

I bought mine from B&Q they were cheaper than Screwfix at the time.

Old houses will have much beefier ceiling joists than a modern build. Mines got 400mm of rockwool up there which makes boarding it difficult though!

My stilts were cheapest from toolstation. Also, my last house was 110 years old and the joists were tiny.

I’ve been measuring up, my joists are spaced 30cm apart and approx. 2 by 4. Cover some big spans though, master bedroom seems to have had some secondary parallel joists added over the top of the originals, presume from when the ceilings was replaced. Other parts of the loft still have the original lathe and plaster visible under the insulation.

I reckon it will be an expensive dirty job but should make a real difference to keeping the house warm.

Follow up question. The roof isn’t felted, would stapling to the inside of the rafters make a difference or better off leaving it?

I cut down 4×2 to make my stilts 200mm high and fixed them with self drilling screws direct to the joists. You can make a fair few stilts for a 2.4m length of timber.

Then I laid 3×1.5 on the tops crossways and filled the void with glass fibre, fitted klober eave vent trays and finished up with loftboards.

The vent trays weren’t enough by themselves to manage the resulting condensation from the drop in loft temperature, but fitting a better seal on the loft hatch did the trick by stopping the seepage of moist air via the hatch.

I wouldn’t go stapling anything on the underside of the rafters as you may just get condensation problems further down the line – unless it were a breathable membrane?

Edit – flapping in the wind and not being able to see what’s between the membrane and slates might be an issue too

Still in researching mode, if I wanted to board it enough it could become an occasional use room would the slilts be good enough? I,m thinking something that could take a sofabed and a tv…

Project begun over Xmas, went for a keylite Timber Wooden Loft Ladder due to it beginning the right width and the fact you can remove the ladder for fitting. Took about 5 hours for first fit. First time using expanding foam, it went nuts and went every where….sounds like everyone makes that mistake….

Also fitted a double led tube light from Costco, about £35 and runs off a plug so instead of running a spur up to the loft (may still do at a later date) just ran the cable down to the socket in the airing cupboard. It’s brilliant lights up the whole loft.

Have decided against removing the old insulation, it is absolutely filthy even though I was using a full p3 mask I’ve been coughing / sore eyes for a couple of days as I think the dust made it into the upstairs rooms, despite me stapling dust sheets to the ceiling around the hatch to make a dust tent.

Next job will be ordering the chipboard, stilts and insulation. Think I’ll do a section at a time as its a big job and I’ve got to work around so,e of the stuff stored up there.

I still have the problem that the roof is not felted and the stuff that I’ve put up there already has a fine layer of dust all over it. What’s the easiest way of sorting this? Ideally iWork’s like to try to contain all this dust so the area up there is usable without a dust mask….

The tops of the joists were condensating due to the cold air hitting the bottom of the joist and travelling up through it hitting the warm floor.

I had a condensation pattern on my dormer ceilings showing the joists when they were not insulated, guess that was the lower temperature due to the mass of the joist compared to the plasterboard. Now have 270mm of space blanket up there which makes a huge difference.
The rest of the loft was already boarded so I just rolled out the 170mm foil backed insulation over the top and kept an area round the hatch for storage. That way you don’t fill the loft with junk that gets binned when you move. Less storage space means you bin stuff you don’t need to keep!