Timber Overlay on Concrete

[swampdog]

Hi,

I have ordered 85mm by 12 mm Tassie Oak T&G timber to lay over a concrete pad. The pad is old (1984), so i expect dry, also Tassie is less humid than most parts of Aus. It seems to me that there are 3 options.

1. Direct stick of the overlay to the concrete using a suitable adhesive.
2. Lay 'Yellow Tongue' first then secret nail overlay to 'Yellow Tongue'.
3. Lay bearers (battens) over the concrete and attach overlay to this. I am attracted to this option since it will allow me to place insulation between the bearers (tassie winters...).

What do people advise? My choice will be based on cost, ease of installation (DIY) and quality/durability of the finished product.

I know that there have been a number of posts on this issue. Problem is I have read them and become more uncertain...

thanks folks,

swampdog

[glock40sw]

G'day.
Don't use Yellow tongue.
Use 12mm ply fixed to the slab with splitz anchours.
Why not go to www.timber.org.au and download the installation data sheets?
It explains everything.

[swampdog]

G'day Trevor,
I have looked over the installation data sheets. It does explain how to use ply. It also explains fixing to battens. It doesn't mention direct fix to concrete.
My priorities are: quality of the finished product, ease of installation and economy (roughly in that order). Is plywood the clear winner? It seems to me that fixing direct to concrete might be easier, and also do away with potential problem of height gain... any advise appreciated.

Thanks for your help mate.

cheers, Swampdog

[glock40sw]

G'day.
Direct stick is not for your everage DIYer.
If it goes wrong, it goes wrong in a BIG way...

Ply gives a better install and is doable by a DIYer.

[swampdog]

G'day

So it looks like ply with the T&G secret nailed to it is the G O. Could I hassle you with a couple more questions...

For my (old) pad do you reckon it is worth laying some sort of moisture barrier if only to be on the safe side?
Do you need to use a cramping technique when laying the T&G over ply?
Do you recommend using any adhesive between the T&G and the plywood as well the mechanical attachment?

Im sure some of the veterans get a bit tired of questions like this... But it is very helpful for folk like me and much appreciated!

cheers swampdog

[glock40sw]

G'day.
That is what we are here for...to learn.

Seal the slab with a liquid sealer. Use Bostik product ( don't know the name).

Glue(with Bostick Ultraset) the ply to the slab and pin with Splitz anchours at 600mm centres.
Leave a 6mm gap between ply sheet edges on all sides.
Now lay a wobble bead of glue (like a snake) on the back of the boards and lay in the usual manner. Again, use Bostik Ultraset Adhesive. Secret nail with a hire gun. The hire place can tell you what length nail to use.

You would be better off sending a PM to Larry McCully or asking Dusty.
They do this schit for a living. I only make the flooring and flog it off to them.

[Dusty]

Swamp dog, following the advice Trevor out laid will see you right.

With the pad, sealing is always a good idea. More flooring problems are caused by moisture in one form or the other than anything else.

In your questions you wrote...Do you need to use a cramping technique when laying the T&G over ply?
By lunch time on day two of being on you knees you will have cramp in your lower back, butt cheeks and hamstrings. All this will be achieved simply by being down there on the floor, no special techniques needed.

However, if your thinking of pulling the boards in tight to each other a chisel driven into the ply and used as a lever can help with bowed or stubborn boards. Although, theoretically, the secret nailer you need to hire is designed to pull the boards tight as you use it. So with a bit of luck and some well milled boards the amount of manual cramping of boards should be minimal.

[swampdog]

Thanks Fellas, youve done me a good turn there. Cheers for the tips on cramping techniques Dusty... sounds like im going to be doing some cramping one way or another!

Job will be started in a week or so, we will see if it all ends happily ever after...

Swamp Dog

[Spelunx]

I am doing 50sqm of decking at the moment, and a pair of knee-pads is the best investment I have made. They are only $12 or so, and will make a huge difference to the ease of the job, and therefore the finished product.

[dazzler]

Hi

What is the advantage in using ply sheeting instead of battens?

How do you secure the first floorboard before secret nailing in the rest?

Cheers

[Wild Dingo]

Hi

What is the advantage in using ply sheeting instead of battens?

How do you secure the first floorboard before secret nailing in the rest?

Cheers

the ply just wouldnt look right mate ... remember hes a Tazweegian propa timber board floors in the shed along with the nice blue chinz curtains the lush pile carpet for insulation on the walls apple shaped light fittings you know that sorta thing

Actually not a bad idea though... dont see that ply would be any better or worse than timber... just use a covering of something or other like epoxy or that other stuff you mix with paint??? bondcrete? thats the one... slather that on both sides and the ply should last a fair few years Id say... the timber looks way bedderah though

DEFINANTLY get the knee pads swampy!! ABSOFRIGGINLUTELY!

[glock40sw]

Hi

What is the advantage in using ply sheeting instead of battens?

How do you secure the first floorboard before secret nailing in the rest?

Cheers

G'day.
Using 12mm or 14mm overlay flooring on battens is no go.
the boards flex too much between centres. Ply is the recommended substrate for overlay T&G installation.

The first few boards of overlay are fixed the same as the first few boards of normal 19mm T&G boards...Glue and Topnail until you get enough clearance to use the secret nailer.

[dazzler]

Thanks Trevor

If I am reading the manual correctly you can use 19mm T & G with battens or 15mm plywood sheeting.

Somewhere I got the impression you can use 12mm T & G with 15mm plywood which keeps the height down a bit.

Am I dreaming the 2nd bit

[glock40sw]

Thanks Trevor

If I am reading the manual correctly you can use 19mm T & G with battens or 15mm plywood sheeting.

Somewhere I got the impression you can use 12mm T & G with 15mm plywood which keeps the height down a bit.

Am I dreaming the 2nd bit

G'day Daz.
For 12 or 14mm overlay, 12, 15 or 19mm ply can be used.

For 19mm T&G 15 or 19mm ply is the go.
The ply and T&G must be thick enough so that the secret nails don't go right through and strike the concrete as this causes the nails to bounce back and you end up with a loosly fixed floor.

[dazzler]

cheers