Reinforcing upstairs floors

lrishJoe

We moved into a our first house, a new build, and had tiles laid in the upstairs bathroom and en suite directly onto the (plywood) underfloor. This turned out to be a disaster as there was too much movement in the underfloor and the grout gradually came away in bits and eventually even the tiles started to lift off the floor. Lesson learned, reinforcement needed!

We're going to redo these rooms now and the plan is to screw down marine plywood to reinforce the underfloor and reduce the movement before tiling.

We're also about to replace the carpets in the rest of the upstairs with wooden flooring. I'm wondering, should we just add the marine pkywood to the entire upstairs to avoid the height difference between the bathrooms and the rest, plus give the new wooden floors a better base?

Thanks in advance for any advice...

brophy

So the floor boards that are currently upstairs are the nailed or screwed to the joist?

I'd imagine they are nailed as practically all are.

My advice would be to get yourself large boxes (20/25mm depending depending on thickness) of screws and screw all the floor boards down this will stop the creaky and squeaky floors happening over time.

Then in bathroom screw marine ply down.

Make sure you are using the right adhesive for wood or that you are adding resin as that gives it a little give also mix resin with the grout to stop cracking.

Goodwin do 200 r2 cutter screws for like 2.75 or so.

Calibos

Had that happen in our renovation. While more screws should have been used by our builders it looked like it was the new joists drying out that were the real problem. ie. Suppliers shoving the joists out the door during the Celtic tiger with too high a moisture content.

orchidsrpretty

No expert but my advice is if you're putting down a new floor, you don't want to take it up again for awhile. so if it is creaky now etc its gonna pi$$ you off probably at a later date, so if i were you i'd go marine ply through-out, and throw down some noise dampening material while your at it, if possible (can you do this between floors? like i said no expert) to lessen footfall noises etc.

Do a job right once and all that..

agusta

lrishJoe wrote: »

We moved into a our first house, a new build, and had tiles laid in the upstairs bathroom and en suite directly onto the (plywood) underfloor. This turned out to be a disaster as there was too much movement in the underfloor and the grout gradually came away in bits and eventually even the tiles started to lift off the floor. Lesson learned, reinforcement needed!

We're going to redo these rooms now and the plan is to screw down marine plywood to reinforce the underfloor and reduce the movement before tiling.

We're also about to replace the carpets in the rest of the upstairs with wooden flooring. I'm wondering, should we just add the marine pkywood to the entire upstairs to avoid the height difference between the bathrooms and the rest, plus give the new wooden floors a better base?

Thanks in advance for any advice...

The grout came away because the tiles didnt bond correctly.No other reason.
Possible faults,
a/ Incorrect adhesive used
b/ You had 3/4 plywood down and its wasnt crossed over with more sheets of wbp or marine plywood or cement board.It absolutely has to be.

Best floor would be 12.5mm cement board crossed over the joints of the plywood that is already there.Bal flexibale adhesive,Bal flexibale grout.All tiles back skimmed as well as putting adhesive on floor.This method is fool proof.
If your going to use wbp or marine plywood,you should clarify with the shop that it is because nearly all the plywood in this country is coming in from china now and its not of the same grade.Its a lower grade!

For the height differents you can use a slightly offset saddle the same material as your timber floor and it will slot in between the tile and timber floor.Bond with tec 7.Its less than 2 inches wide

ps. I would be fairly sure the fault is not down to movement in your floor

BryanF

If you lay marine ply, the floor will be approx 15/20mm. This will impact your last step (riser) - all stairs risers should be equal.

lrishJoe

Great stuff guys, many thanks for the info. I'll have to have a better look under the carpets but it sounds like marine plywood for the bathrooms and extra screws for the rest is the way to go.