Hi Everyone! I would like to instal 140x19 merbau decking over glazed tiles. Using the 140x19 as cross member support at 600 centre, as well as the decking. I don't want to screw or nail, just using glue. Has anyone tried that successfully?
Hi @dh411,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
Unfortunately, laying standard decking boards directly over the existing tiles isn't something I would recommend.
Decking timber isn't designed to sit directly against the ground or another solid surface like this. There needs to be adequate clearance and airflow underneath the boards so that moisture can drain away and the timber can dry. If the decking is sitting directly on the tiles, water can become trapped underneath it, which is likely to cause issues with mould, deterioration and premature decay.
If you'd like to use conventional decking boards, you'd need to construct a low-level decking frame above the tiles, so the boards are properly supported and separated from the surface below. The available height between the tiles and your door thresholds will be an important consideration here, as even a low-level deck requires space for the supporting structure and adequate drainage. Check out How to build a low-level deck and How to build a deck for some guidance.
Alternatively, something like decking tiles would be worth considering. These are specifically designed to be laid over an existing hard surface and have a raised backing that keeps the decking material separated from the surface below while allowing water to drain.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
Thank you Jacob for your input. I should have mentioned that the patio is under cover. Also I will use 140x19 boards at 600 centre as cross members. My concern is the fastening. I theory glue should be efficient to hold it all together and fixed to the floor. I have no experience with gluing the deck instead of using screws. Can you advise about adhesive?
Thank You
Dieter
Hi Dieter (@dh411),
Regardless of whether it is covered or not, it is still not advisable. Any moisture, regardless of source, whether it is a spilled drink, or rain that is blown sideways into the patio, will sit underneath your decking unable to dry out due to lack of airflow or sunlight. This moisture will lead to issues, both with the decking and with the decking that is in direct contact with the ground.
In saying this, you can choose to do it if you wish, but we wouldn't advise it as issues are pretty much inevitable.
If you were to do it, I'd recommend using https://www.bunnings.com.au/ramset-7-x-50mm-green-wall-plugs-25-pack_p2260646?store=7369&gclsrc=aw.ds&gad_source=1&gad_campaignid=21122993677&gclid=EAIaIQobChMI042U3ezWlgMV0CqDAx0CWwEaEAQYASABEgL_i_D_BwE with screws, as opposed to adhesive. Adhesive alone will not resist the lateral forces that would be applied to your deck, meaning it would almost certainly shift laterally over time.
If you absolutely had to use adhesive only, I'd use a general construction adhesive such as Liquid Nails, and use a very generous amount of it.
Allow me to tag some of our helpful members for their thoughts - @MikeTNZ, @Nailbag, @Dave-1, @Noyade.
Good Evening @dh411
I have seen the decking tiles that @JacobZ has suggested and would also suggest to use them on tiles. I understand your idea for a low level deck and "waggles hands" Id consider it in a worst case sceneriao. There is almost no thread for a screw to grab onto the base boards you are suggesting. Glue will fail for sure and probably in a very short period of time.
If you can supply a few photos of the area you are wanting to install decking maybe one of us can come up with an alternative solution.
I would strongly suggest to have some more thought about the deck and height you have to play with.
Dave
hi @dh411
Regardless of adhesive and clamping method, as @JacobZ has already mentioned you simply won’t get away with gluing battens between joists and boards down on to joists.
Subfloor aside, deck boards need fixed screws or nails just to help align each board straight as they always have some level of left/right bow.
Why the need to glue?
Nailbag
"I don't want to screw or nail"
Same thought as @Nailbag above - can you share the reason why? If you no longer love the glazed tiles would you be comfortable drilling through them" - thinking concrete screws…
Just being curious @dh411. Cheers.
