Bringing the subfloor up to an inch

9 years ago

My bathroom subfloor is 1/2 (5/8?) inch plywood and for support I would like to increase it to an inch. My understanding is that:

1) the first layer of plywood is fastened to the joists but the second layer is fastened only to the first plywood layer - not the joists too - too allow for movement/expansion.

2) a very thin layer of thinset should be spread across the lower plywood layer to fill any voids between the two plywood layers.

3) and I have no understanding whether nails or screws are better for this purpose. Any knowledge on this?

I was going to use Ditra but have discovered Strata Mat which allows use of modified thinset mortar -- any opinions on these products? While 3/4 inch plywood is considered sufficient I wouldn't mind bumping to an inch or 1-1/8 inch.

Sort by:Oldest

Comments (5)

PRO
By Any Design Ltd.
9 years ago
last modified: 9 years ago
I posted some more info on installing Strata Mat on this blog post of mine.

INSTALLING SMALL MOSAIC TILE OVER STRATA MAT

Not sure why I thought I could use the Strata Mat with such a small tile but the repair I showcase works and is in line with what other uncoupling membrane supplier recommend for small tile installs over uncoupling membranes. In hind sight NobleSeal CIS would have been a better choice for that job.

But the photos show how well the coverage checks can be seen during install. You get a nice visual confirmation. many of the Strata mat showroom displays are poorly built. They do not show proper coverage. I don't know why but the one here in Burnaby is a joke.

Here is an install picture - this is my buddy's house.

This picture shows the process - I have yet to smooth out all the thin-set. If you see the faint dark spots on the mat those are where the thin-set from below is locking into the top section through the breathing tabs. I love this a lot. the mechanical connection (be it ever so slight) from bottom to top.

I have viewed effloresce lines in tile jobs before that appear to be on 3' centers. This could be from moisture migrating between seems of a waterproof membrane. This membrane allows even moisture migreation and better curing I think.

This advertising photo is like the sample I see here in Burnaby

If the product looks like this you are not really locking the thin-set 100% to the backer fleece. The bond is in this fleece and the reason why the Strata Mat is clear ish.

Here is another shot showing a larger bathroom and more Strata Mat.

Strata Mat is also a little wider than Ditra. This is an added bonus and allows for less seams. On the project shown below we used two kinds of Slate - both required modified thin-set for installation. So here the Strata Mat worked well again.

Below the Strata Mat on this job is a electric floor heating cable from Cosco. All the thin-set to install it needs to cure - here again those little relief cuts allow for even curing under the tile install.
PRO
@designREMODEL Baths, Kitchens & More
9 years ago
Strata Mat is a great product. Much better then Ditra for ease of use. Really like that you can see how well it embeds into the thin-set and the vapor holes are key in insuring that the thin-set sets properly.
Related Discussions
Need help for terrace room to cover iron bars
Q
Comments (4)
thanks for the great suggestions! Will speak to the archi. to check if the bars can be reduced in numbers.One suggestion from his end was to cover these bars by using cement fibre sheets that have the look n feel of wooden texture but I am not sure of the end result.Any other material that can be used to enhance the look?
...See More
i need help for my formal living and unformal living and dinning
Q
Comments (300)
I think a comfortable distance between the island and the counter is around 42". It seems that you have only 30" between your cook top and the counter. I might be a little too tight. The wall between the entrance and the kitchen could be 4' long instead of 6', you would then be able to move the island a foot which would give you more room between the cook top and the island. Could you switch the location of the toilet and vanity in your dad's bathroom so your enter facing a vanity instead of a toilet which is a lot nicer.
...See More
Planning for disability
Q
Comments (228)
Tsilanko, I would always recommend professional installation where needed. But what I am doing here is suggesting that WHEN you are planning to build or renovate, to consider how your plans will affect you in 20 or 30 years time. Split levels are very hep when you are young. A kitchen 3 steps down at 30 is rarely a problem, but might be a hazard at 60, or, as Marjie1059 suggested, if you break a leg. ... All my parents' homes were terrible for old people. They were forced to move to a bungalow in extreme old sge because the location and design of their home was more suitable for an active young couple with a large family than for an elderly couple with stroke disabilities. I would not want to move again, so my present home has features built in that make ageing in place simpler. Mostly small changes, like grab rails, and lever handles on doors and faucets. A major disability suddenly suffered requires major changes if permanent. I did look at this because it came up in the discussion, but if you look at the heading, Planning for Disability, it means just that. Plan ahead so you don't have to make expensive changes later on. But thank you for your advice, yes, major changes are not in the DIY domain.
...See More
Backyard Landscaping
Q
Comments (5)
As far as spacing between the pavers, you want a minimum of 3mm or ⅛ an inch, but the ideal spacing really depends on the whole space and how you want to fill the space between pavers. If you are thinking about pea gravel or sand, you probably want less space between to help keep your costs down and make it easier to power wash. If you are looking to add greenery then more space between the pavers gives you more green, creating a more natural-looking space. If you do decide to go the gravel route, you can apply a clear coat of something like gravel-lok. It acts like glue, keeping the gravel in place. It may not be able to take the full force of a power washing, but it will certainly hold the gravel in place better than not having gravel-lok. If you do want to go for a green option, grass could work, You could also look into small succulents, moss, or clover. With any green option, you will have a little more maintenance in the form of trimming and watering, but the look is stunning! You absolutely can put grass between the pavers. It will actually help stabilize and hold the pavers not move them. (if installed correctly) I would space it 4” apart and use netfin or a similar subsurface drip line to water the grass underneath the soil. This look is probably my favorite but you could also use a crushed aggregate in between too. Gravel is a terrible idea because it doesn’t stay in place. Here are some ideas from our projects of all kinds of paver designs:
...See More
User
9 years ago
last modified: 9 years ago
Cataan , to answer your questions:

1. Correct . Screws from second layer do not penetrate into the joists. The 2nd layer sheets do not line up over the joists or the first layer either.

2. NO, do not place thinset or construction adhesive between the layers of plywood. You may use a FULL spread of wood glue l tite bond II, but it is difficult to accomplish, and I doubt you'll find many construction guys willing to pour and spread the glue with the proper trowel anyway. It'll take A LOT of glue too.

3. Screws are better, but more costly and take longer to install. They may also require a counter sink hole depending on the brand and type of screw you use.

What kind of tile are you thinking about using ?
cataan
Original Author
9 years ago
Thanks. 12x24 porcelain in a stacked/soldier pattern on top of strata-mat. No lipping allowed!
PRO
By Any Design Ltd.
9 years ago
"No lipping allowed!" - LOL I was just going to call you a Bad Name.... or did you mean no Tile Lippage....

Bringing the subfloor up to an inch

Comments (5)

By Any Design Ltd.

@designREMODEL Baths, Kitchens & More

Related Discussions

User

cataan
Original Author

By Any Design Ltd.

COMPANY

EXPLORE HOUZZ

CONNECT WITH US

Bringing the subfloor up to an inch

Comments (5)

By Any Design Ltd.

@designREMODEL Baths, Kitchens & More

Related Discussions

User

cataanOriginal Author

By Any Design Ltd.

COMPANY

EXPLORE HOUZZ

CONNECT WITH US

cataan
Original Author