Do Not Sell My Personal Information Jump to content


  • Join The Club

    Join the Lexus Owners Club and be part of the Community. It's FREE!

     

Loft Insulation And Boarding Up


Recommended Posts

I've just completed two thirds of my loft adding 8 inches over the top of the existing insulation ( special offer in B&Q ).

I've got the centre section to do which is part boarded, part water tanks and a small part insulated four inches to the joist tops. So a few questions to those in the know:

1). is it true you should not insulate under the tanks?

2). I've currently got four inches under the boarded area ( approx 14 foot by 9 foot minus the hatch ). If I want to increase the insulation here I need to lift the board ( plain chipboard cut to suit not tongue and groove ), if I put new insulation down but compact it under the boards will it still give increased insulation? e.g say 12 inches compacted to 4.

3). current boarding is a bit iify in places ( it gives when you walk on it ) and one part got wet and gives a bit more :(

4). So do I put the existing stuff back down and put more on top or just put new stuff down

5). what is the best and easist stuff to put down baring in mind it will need cutting to fit and then fixing to where the joists happen to be. Standard gap distance is 24 inches, but I guess there will be some cross bracing around the hatch.

Any comments welcome.

Link to comment
Share on other sites

Pointless compacting the insulation material as it will then give less insulation. If you want to increase the depth of it you will need to increase the height of your joists. As for boarding, VFM wise, flooring grade chip is probably best. I would take up any damp/damaged flooring anyway. Best to put new down rather than overboarding. Insulating under tanks stops any internal heat from helping to stop them freeze up but not sure what "official" policy is.

Link to comment
Share on other sites

don't insulate under cold water tank as heat rises and stops it freezing.

replace old wet lagging as this is ****** and will be useless and as said above compacting it reduces it's effectiveness.

im a thermal insulation engineer (lagger) :)

Link to comment
Share on other sites

check your electrical wiring !

by covering them with insulation you lower the current carrying capacity of them :whistling:

keep them running parallel and clipped to the highest part of the joist and leave some air gap round them

Link to comment
Share on other sites

I've always used the Wickes loft boarding which comes in a size to fit the hatch and with a bit of pva glue on the tongue and groove the joint doesn't need to be on the joist.

I've always wondered how much boarding increases the insulation but haven't managed to find out.

Link to comment
Share on other sites


Bazza - what I read was normal electic cables were OK but electric shower cables and the like with higher current need to be over the insulation. That's what I've gone with.

any and all cables are subject to heat overloads due to insulation

an example is if a cable is wrapped in insulation it has to be down rated in current carrying capacity by 0.5

so a normal 1.0 mm lighting cable that is rated 16 amps, when wrapped in insulation is only rated at 8 amps

which is not a great concern if its protected by a 6 amp fuse, but is when a 10 amp fuse is protecting it !

the bigger the cable and load the worse it gets

a shower circuit rated at 47 amps gets reduced to 23 amps

Link to comment
Share on other sites

Latest Deals

Lexus Official Store for genuine Lexus parts & accessories

Disclaimer: As the club is an eBay Partner, The club may be compensated if you make a purchase via eBay links

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share






Lexus Owners Club Powered by Invision Community


eBay Disclosure: As the club is an eBay Partner, the club may earn commision if you make a purchase via the clubs eBay links.

DISCLAIMER: Lexusownersclub.co.uk is an independent Lexus forum for owners of Lexus vehicles. The club is not part of Lexus UK nor affiliated with or endorsed by Lexus UK in any way. The material contained in the forums is submitted by the general public and is NOT endorsed by Lexus Owners Club, ACI LTD, Lexus UK or Toyota Motor Corporation. The official Lexus website can be found at http://www.lexus.co.uk
×
  • Create New...