Screwed down ply

Another thread just reminded me of something unpleasant that caught me out a couple of months ago. The builder had constructed a small extension c/w patio doors with chipboard floor and overlaid it with well screwed down quality 6mm ply and it appeared spot on. Shortly after I fitted Amtico black tiles some little bumps were appearing. They turned out to be where some of the screws had displaced and raised the ply. The bumps were minute and couldn't even be felt by touch but owing to the light and the finish of the tile every tiny flaw showed up. It caught me out as I always use my nailer which doesn't raise the ply. Cost me a days work for two and two boxes Amtico to fix.

So all screwed down ply gets sanded down all over now.

 

Do you feather over ply ?

 

Just the joints but I'm not sure it would have made any difference as they were high spots. If it seems dead flat I don't see the point in messing with it

 

Either had I. Black Amtico tiles and big windows aren't very forgiving.

 

Sound like poor quality ply to me where some of the layers are separating . Had it before mate. If it was me fitting amtico I'd only use the top grade ply , yeah it costs more but you don't get any issues like this.

 

Flexi screed? Better off using a thicker top grade 9mm ply which will give more stability screwed down well, then feather over the lot . Be like a billiard table.

 

we always flex or feather finish ply all over, its not worth the problems if they do show afterwards , prevention is better than the cure

 

I've never seen the point of flex screeding over a plyed chipboard floor that is already smooth and flat ....it can't make it better but possibly make it worse and at a price. Chipboard isn't hard to establish if there are likely to be problems with light by using a fine straight edge along with some experience. Sometimes the joints may be slightly raised which I sand down prior to plying. Sometimes there might be a slightly high joist underneath which may need a flexy screed all over. Very good point with the feather screed but I reckon it is good to fill low spots and doesn't eliminate high ones. Anyway the issue is sorted as I sand over all surfaces ( including chipboard joints prior to plying ) using my new toy as mentioned in another post and the results have been excellent.

 

I always flexy ply aswell 3mm ply and flex cost not much more for a better finish

 

What flexy are you using? Stopgap 700 sure aint cheap? I mean a 12-14 sq.mtr kitchen would need three bags plus the time to screed the job

 

Touch wood since using SP101 ply I've not had a problem. So I'm back to
Sort floorboards out, ply ,feather joints.

The 60m2 Amtico job I have just ripped up was 9mm plywood feathered joints. All delaminated.

 

I know daz me too. I use that top grade ply its the dogs danglies. Yeah it costs more but it saves u in the long run having problems. Plus if you all use flexy screed that's not cheap. All you need is a tight coat of feather on top and away you go.

 

agreed me too, but getting the extra coin for it is tricky especially when others will bang it in much cheaper.

 

Do any of you lads have folder with your jobs to show customers if so do you have a section of when jobs go wrong? obviously not your own, but explain to the customers about prob seeing board outline in a couple years etc then a couple of pics of boards showing through normally helps them part with a bit extra xash

 

Interesting thought. I always talk about what can happen with duff plywood or going without a dpm but never thought about the gory pics. My first thought is to get jobs by talking positively but I suppose you you're planting the doubt and then offering the solution