Boarding a Loft with Low Ceiling Height - Previously Boarded on Joists

[uptoyou]

Hi all,

Had a small leak in the roof last year and about a month ago I went into the loft and the whole roof was literally dripping with condensation.
Now it has cleared I need to give the loft a proper do-over.

Joists look to be around 100mm and insulation is throughout - some areas up to the top of the joist, other areas all bundled up in various ways.

The previous owner has boarded directly on to the joists along the whole span of the roof space, and probably 1/3 - 1/2 total either side.
Although I can't quite tell, I expect there is insulation underneath the boarding.

I would like to re-lay the insulation with new (if new is needed), and board over the majority, but it looks like I would need to raise the joist height (using loft legs perhaps), only the roof is very low - somewhere between 1.2m - 1.5m at it's highest, where it then drops quite steeply either side.

What are my options here? Adding loft legs (smallest I think are 175mm), will make the space even more unusable due to the height?!?

 

[oldbutnotdead]

If headroom is that limited, maybe give up on the idea of having it boarded out. I'd suggest getting rid of that horrid yellow stuff (it'll be full of dust and will probably compress down to nowt if you try topping it up) and replace with current advised thickness (100mm between joists, 200 above, don't block the eaves).

 

[uptoyou]

Thanks for the response
Taking another look, and based on the attached image, I think you're right and fully boarding it out will be the wrong choice.
However, I need the space for storage (its pretty rammed up there), so need to retain some boarded up area...also just measured, and height is around 1.05m!!!
Approximate layout and dimensions attached, and you can see how tight it is right behind the hatch with the rafters.
Would it be reasonable to retain an immediate area around the hatch, boarded straight onto the joists as it currently is just to allow easy access - possible 1m all around, and then add loft legs to raise it an additional 175 to incorporate more insulation and retain some storage space?
Any other creative suggestions?
1st pic current layout, 2nd pic alternative?

 

[oldbutnotdead]

It's your ceiling- I made the decision (when moved from house with large loft space to very limited loft space) to decr*p the loft.
Yes you can do what you suggest- thermally you'll get better results with the thicker insulation. If space up there is that valuable, consider using PIR board between joists under the low boarded-out bit instead of loft roll (PIR per millimetre thickness is about 50% more efficient than same thickness of loft roll).
Again if desperate for space you could use PIR instead of the legs (trouble is you'd need to board across the joists to support the PIR then board over the top to support your Stuff. But the top boarding could be cheap laminate.....

 

[uptoyou]

Will definitely go for PIR under the low boarded out part, but what do you mean by using PIR board instead of legs - lay the PIR at 90 degrees to the joists and just sit it across the rock wool filled cavity, then build a 'platform'over it?

 

[oldbutnotdead]

Will definitely go for PIR under the low boarded out part, but what do you mean by using PIR board instead of legs - lay the PIR at 90 degrees to the joists and just sit it across the rock wool filled cavity, then build a 'platform'over it?

Pretty much- you'd need boards over the joists (under the PIR) to support it and boards on top of the PIR as loadspreaders - as before, cheap laminate would do.