Boarding the loft out

[audi321]

Hi all, I'm thinking of boarding out the loft for storage and maybe a scalectrix track for the kids (bungalow so a large loft!).

Do I need to do anything about the joists (roof trusses). I know if it's a permanent bedroom or something like that, I need planning permission and building regs, but this is just going to be a DIY project and I really don't want the hassle of installing new joists, etc, etc.

Am I going to be ok just getting those loft sized chipboard sheets and putting them down?

Thanks for any advice!

[zaphod42]

I can't help on this topic, but grab a copy of the Collins DIY manual - Amazon normally has them cheap (esp used ones) or a charity shop - I think it covers that, and all the other related work as well like lighting / insulation.

It's good on the basics and the more complex stuff - plus importantly it tells you what work has to be done by an electrician, etc vs what you can do yourself...

[zcacogp]

I boarded some roof trusses above a garage for my parents a year or so ago and did just as you said; bought boards and screwed them down. There was already lighting up there and I added a couple of extra sockets to an existing ring main to give them power up there. (Given that we were starting with just trusses I also screwed some plasterboard to the underneath of them and insulated between the layers, and put a loft hatch in.)

It was very easy and very satisfying. I reasoned that if the trusses were strong enough to support someone standing on them then they would be more than strong enough to take the weight of a couple of people, given that this weight would be spread around by the boards.


Oli.

[Du1point8]

if the loft has insulation do you not need to secur it in chicken wire if you intend to board out the loft?

[audi321]

Du1point8 said:

if the loft has insulation do you not need to secur it in chicken wire if you intend to board out the loft?

There's not much insulation up there, I recon it will squash into the joist depth

[Du1point8]

audi321 said:

Du1point8 said:

if the loft has insulation do you not need to secur it in chicken wire if you intend to board out the loft?

There's not much insulation up there, I recon it will squash into the joist depth

might be worth doing anyway if you intend to use it later as its part of the fire requirements if I remmeber rightly

[AndyClockwise]

Or you could use boards that are backed with solid insulation so that you increase the warmth of the house at the same time (although it would be cooler in the loft itself)

[CIS121]

Squash the insulation and it will be less effective.

The standard rafters (4"?) should be strong enough to board and walk on. If you've lathe and plaster ceilings below, you might experience some cracking.

[Sam_68]

Be conscious that Fink trussed rafter roofs are not designed to take large ceiling loads (and are held together with 'gang nail' plates that are only effective when loaded in the way they were designed for).

Also be concious that restricting airflow over the insulation quilt in lofts (either by boarding over them or by subsequently storing a load of boxes up there that themselves restruct the air circulation) can lead to problems with loft condensation.

Lots of people will (quite truthfully, I am sure) tell you that they've done it and not suffered any problems, but I've also seen plenty of instances where people haven't been so lucky and have ended up with damp problems or distortion of the roof structure.

[Blakeatron]

Just doing ours now;

Cross joist the ceiling joists with some 3"x2", fill void with insulation then floor with 15mm flooring chipboard.

Roof joists - staple on insulation (foil wrapped bubble wrap) about £90 for 12sq m. Cross batten with 2x1" slate lats and then board over with 15mm Mositure resistant MDF. Nail some small battening over screw holes. emulsion everywhere and then lay old lounge carpet.

I will also be building 2 stud walls, 1 on the joining gable and one in the centre of the house, this will just be 3x2, insulated, battenend and boarded.

It should of been insulated more, but this is only a bit of clean storage - it will never be used as a room.

[FlossyThePig]

Beware!

My father put boards down in their loft. The weight of the stuff he put up there started to cause cracks in the walls below.

Their previous bungalow they owned had been built with conversion in mind and all the joist were big enough for proper flooring and the walls were strong enough to take the load.

[stabbed rat]

OP - I might be able to help you on this too, depending where you are and if you have a large enough vehicle we may be able to supply the boards for you. I may be able to wing it for free for you, if not then at a small cost.

[Defcon5]

Sam_68 said:

Be conscious that Fink trussed rafter roofs are not designed to take large ceiling loads (and are held together with 'gang nail' plates that are only effective when loaded in the way they were designed for).

Also be concious that restricting airflow over the insulation quilt in lofts (either by boarding over them or by subsequently storing a load of boxes up there that themselves restruct the air circulation) can lead to problems with loft condensation.

Lots of people will (quite truthfully, I am sure) tell you that they've done it and not suffered any problems, but I've also seen plenty of instances where people haven't been so lucky and have ended up with damp problems or distortion of the roof structure.

I have this type of roof (house 2 years old), I have wanted to do the loft since we moved in, but darent because I am scared the roof will cave in or something!

What would be classed as a large load? A floor full of loft boards must weigh a good 100kg

[russ_a]

Check out diynot.com and see all the posts from people where it has gone wrong.

Didn't stop me part boarding my loft though

[Sam_68]

Defcon5 said:

What would be classed as a large load?

Unfortunately, that's a 'how long is a piece of string' question; it will depend on lots of factors, like teh span of the roof, the weight of the existing roof slates/tiles, how much intermediate support there is from internal walls (Fink trusses are designed to span from external wall to external wall, but obviously deflection is limited if they have intermediate support) and - possibly most importantly - how localised the loads are from the stuff you store up there.

Unless you are dumb to the point of Darwinism kicking in, it's unlikely to collapse; you're more likely to see distortion of the structure over a number of years. And condensation caused by limited airflow is a far bigger and more prevalent issue than structural failure.

[Defcon5]

Would it be ok just to board a bit of it, condensation wise?

[Sam_68]

Defcon5 said:

Would it be ok just to board a bit of it, condensation wise?

Again, hard to say, unfortunately, as it depends on too many variables.

The way the problem occurs (traditionally at least - there may be another mechanism at work in modern houses, but let's not muddy the water) is that warm air loaded with moisture from cooking, washing and respiration filters its way out into the roof space, cooling as it goes. As it cools, the air can't hold all the moisture, so it dumps some of it out as condensation into your nice, absorbent fibreglass insulation quilt. The insulation quilt then relies on the air circulating in the loft space to dry it our during the warmer periods.

So... you've got all sorts of variables to consider, like:

• how much air can leak from your ceiling into your loft space (foil backed plasterboard ceilings, tight fitting loft hatches and no holes for downlighters help);

• how much insulation quilt you have (thick quilt takes longer to dry out when it collects condensation, but if you have thin or no quilt you lose a lot of heat and you'll just get condensation and mould at ceiling level on the inside, anyway).

• How well ventilated your bathrooms are (so that you get rid of the moisture before it finds its way into the loft).

• How well ventilated the loft is, and how even the air circulation is within it.

• External temperature profile and humidity (we get a massive peak in problems late autumn, when you get damp, cold air outside, so the loft doesn't dry out no matter how well ventilated it is).

The bottom line is 'cold' roof structures (ie roof with insulation at ceiling level and a cold loft space above) are pretty marginal at best and with modern insulation levels, it's not unusual to experience problems - sometimes severe ones - even without restricting the airflow by boarding the loft out and putting stuff up there ...anything you do will increase the risk, but it's difficult to predict when you will reach the tipping point.

Edited by Sam_68 on Monday 11th July 07:51

[russ_a]

When I did mine I made sure I didn't cover above the bathroom and used 2x2 battons to stop the insulation getting too squashed.