Attic Flooring

Triman111 · 07-09-2021 5:16pm #1

hi there, got a quote today for decking out my attic with the standard 18mm tongue and groove flooring. The guy was saying that I need two layers due to thickness of insulation, etc. If we went with one layer, it would just cause the insulation to compress. price is a good bit higher as a result. Just checking if this all makes sense as I don't know much about attic flooring!!

10-10-20 · 08-09-2021 8:04am

He's probably referring to raising the height of the ceiling joist rather than using two layers of T&G. You don't want to compress the existing insulation by putting T&G down on top of it.

They do this by running new wooden supports (battens) across the top of the existing joists to increase the height to 300mm or more. Yes, it would add to the cost as wood is expensive just now, but that's likely to be the proper job. Get further quotes, is also good advice.

Corkey123 · 08-09-2021 11:43am

Would attic stilts not be a cheaper solutions? If you need the floor for just general storage the stilts are ideal. But if you need an area to walk on then the raised joist is the better option, but expensive.

Also give consideration to access to pipes and cabling in the future

Triman111 · 08-09-2021 7:27pm

Thanks both for your replies. Im just wondering if this is a job I could take on myself...just get the material and tip away with it....

EmptyTree · 17-09-2021 6:39pm

Can you let us know how you get on, I'm in a similar position myself and I'd be interested to hear how it works out for you in the end.

Triman111 · 20-09-2021 9:38pm

I'll let you know for sure, maybe we can share ideas. I'm thinking of goin with stilts. just going to try to source the 18mm T&G as cheap as possible. I think it should be straightforward but mite taker time!

Markcheese · 20-09-2021 9:50pm

Don't the stilts usually get used with sheets of timber Rather than planks ?

awec · 21-09-2021 4:54pm

Remember to make sure you buy timber that will fit through your attic hatch.

cheif kaiser · 23-09-2021 11:32pm

Did my attic some years back and screwed 2 x 2 timber on top of the attic rafters, I then laid the t&g flooring on top. Was easy enough in my opinion.

I am of the Female variety :)

Up Donegal · 26-09-2021 12:06pm

Would plywood be a cheaper option than T & G boards if it was cut to the largest size that'll fit through your attic hatch?

Dr_Colossus · 26-09-2021 6:31pm

Plywood as is all timber and sheet boards have gone made expensive. Could look at 8'x4' OSB sheeting and cut to size before lifting into the attic. Usual flooring is 8'x2' tongue and groove.

What's the make up of your joists and rafters, in my case I had those pre-fabricated W shaped trusses making any flooring a nightmare with multiple cut outs (not like chief kaiser's clean install above). Early last year I got the small loft packs (sheets of 4' x 1', link below) which made installation that bit easier. Prices have gone up massively since, I got 15 in total, initial lot in Feb 2020 for €10 a piece and a 2nd batch around May 2020 which were €13 and those same packs are now €21. There was still a lot of cutting and measuring required to fit in around all the obstacles however.

My existing joints were only 100mm with same insulation in between so I raised the flooring and insulation up to 400mm total, cross battened with 150mm x 35mm and crossed those again with same and sleeving all electrical cable in between.

https://www.goodwins.ie/products/osb-loft-pack-1220x300mm-18mm-x-3-1-1m2.html

Triman111 · 10-11-2021 7:44pm

So I originated this thread two months ago so coming back now to post how I got on, hope @emptytree reads this :)

Long story short, I did the whole job myself. Originally I had no intention of taking in on, but I got a quote from a guy whose name I wont mention. It was a fair quote to be fair to him, but I haggled and he got the hump :) I would always haggle when taking on a job. If the guy takes it well and gives me nothing, then I actually like that in someone and I'd take it that the guy is genuine both in terms of the price and also his character.

So yer man got the hump, which to me reflected poor professionalism. Word of mouth/reviews is huge in this type of game not that I'd be taking to social media or anything but if I was asked for an opinion I wouldn't be too complimentary :)

So this led me to deciding, let's take it on myself.

I would be an average DIYer, that's important to know.

My area was 30sqm. First step is to measure the area and buy the right quantities of 18mm T&G flooring. It's important to know what way you will need to cut the lengths in advance so you order the right quantities. If you read my original post, you will probably see that I was a bit green on the idea of raising the floor level. All this means is not to lay the boards down on the insulation, they need to be kept 200mm above the joists so as not to compress the insulation. As per the advice that the guys here helped me with, I decided to put the floor on stilts. It worked a treat. For 30sqm of flooring, I bought 24 sheets of T&G flooring and I bought 10 boxes of 175mm stilts (12 in a box). Total cost including screws came to about 900e.

It took me a while to get going but once I found the groove (pun intended!), I started motoring. I did the job on an off over about 3 weeks but was flying it near the end once I knew exactly what to do.

Key learnings:

Watch videos on youtube in advance.

Put the screws into the base of the stilts before drilling them into the trusses. A lot quicker and this can be done outside of the attic before u bring them up, even as you are watching TV.

No need to get stainless screws, zinc coated ones are fine and much cheaper as I learnt after.

The grooves of the boards have a long side and short side, the long side goes on top, they fit in much neater this way, copped this after I was halfway through but no impact.

Major tip, if you can design your flooring so that if you are making a cut, that you cut across the 0.6m width, you will generate less waste this way. Also I was cutting by hand so much easier to cut by hand this way as opposed to the long way. I also reused the sections that I cut by putting them together in certain areas that suited, doing it this way I actually only used 23 sheets out of 24 and have on left over.

It's on one of the selling sites if anyone wants it.

Overall I saved about 400 euro doing the job this way and avoided any risk of the guy charging me extra for stuff...which was a reasonable risk as the guy had quoted me w/o seeing the attic.

And I actually enjoyed it and learned loads. I would recommend anyone with a moderate DIY ability to take it on if it's just for storage like in my case. You would need to be of a reasonably patient disposition though as it takes a bit of time and patience. Hope this helps....I come back to anyone who has any questions.

10-10-20 · 11-11-2021 8:51am

Well done. What spacing did you use with the stilts and do you find them stable?

Triman111 · 11-11-2021 9:39am

each board 2.4 x 0.6 would need stilts, but the key is to try to share them at the edges with the adjoining boards. The location of trusses won't always allow this though :)

Triman111 · 11-11-2021 9:40am

each board 2.4 x 0.6 would need 6 stilts I meant.

cruizer101 · 11-11-2021 9:59am

Planning on doing this myself, the stilts definitely seem like the right job.

Currently is 100mm of old saggy fibreglass so plan ripping that out and putting in 300mm total and just flooring central part of attic with stilts.

Whats the advantage of tongue and groove? I plan just butting osb or ply up against each other, they are screwed to the silts anyway so gaps shouldn't widen and with the insulation below I don't see any advantage to the tongue and groove sealing the gaps.

okedoke · 11-11-2021 10:08am

Are the stilts stable & sturdy enough to walk on without risk of damaging them. Also, sounds like you had a 2nd layer of insulation running across the bottom layer (as I do)? - if so was peeling back the top layer to lay the stilts a big job?

Triman111 · 11-11-2021 10:20am

@cruizer101 I am no expert but just to say that the stilts are flexible. They are super in terms of vertical support but they can move left a right. That's where the T&G comes in, the help a lot in this regard and they do provide a sturdier fit in the horizontal plane. But it depends on how good a carpenter you are if you use normal board I'd guess. @okedoke, absolutely no issue with the stilts for walking on provided you use 6 stilts per 2.4m x 0.6m board. I mean I wouldn't put Mike Tyson on it, but I'm 14st myself and no issue walking on it.