On old quarry tiles with no dpm under them, is it best to screed dpm 1 or 2 coats then screed again or dpm straight on quarry's then screed over?
The new rules are that you cant apply a surface DPM to a subfloor that does not have a working dpm under it. The floor must be dug up. So basically any solid subfloor that was laid before 1965 should be removed and replaced with new. However, use 200 stopgap over the top and 2 coats epoxy. Providing you get a good bond on the screed it will be o.k. But like i say its not approved to do any more.
But you would anyway Matt,well you would advise me to would you not?,especially with the technology today!.
So what people high up are saying is floors with 9x9 vinyl tiles on an no dpm underneath should have the whole subfloor taken up and relaid with concrete or asphalt? If that's the case it's crazy because customers won't pay that kind of money. I laid a Karndean floor in 1996 in my 1st house, I rent it out now to my auntie. It hasn't gapped or lifted and has been down 15 years. The subfloor was old 9x9s down on concrete. House was built in about 1930 so no dpm under it. I uplifted the tiles and screeded it with screed master 2 I think. Laid planks with f44. Will bring this all up next week at the f.ball course. They won't be able to shut me up with all my questions.
F.ball told me I couldnt use 200 under a dpm even though I thought it was the same as the old 55 and green bag which they use to recommend. They told me to use a then new product 900, maybe it was just me but that stuff was impossible to trowel out. I now use ardex na alway. I used to like 200, can I go back to it then?
I have been using the lay bond system for years an no probs. Prime, black magic, dpm, prime, screed master 1. But want to change to f.ball system so I can use 300 hd
900 DPM prep is crap. When it first came out i had loads of people telling me they was having issues that i feed back to Fball. Anyway, the issue with DPM over subloors with 'no' Dpm is the fact that pressure can build up and blow it off the floor. So manufactories now so you cant do this due to lots of them failing. However, there is alot of reasons that can cause it to blow. 1st main problem is the water table etc where the house is built. It it is high it can blow it off the floor. The next issue is bonding your screed to the floor. Over the last few years most products are now waterbased and now we have this new VOC tests. The products simply cant deal with moister anymore. Getting back to teh water table, for a example for you. If you have a swimming pool in your garden and you empty it, there is a chance the swimming pool will actually 'blow' out of the ground. Under the swimming pool will start to fill with water (like under your DPM) and without the weight of the water in the pool to hold it down the pool will simply end up lifting out the ground. This is no diiferent to pressures you will apply to the dpm. Its all down to how much force is there and well it is bonded.
I believe its called Hydrostatic pressure Matt and their ain't no DPM that holds that back Kings Cross suffers from this to the point the one I saw that failed not only pushed up the vinyl, the latex, dpm, and the conctrete sub-floor to.
Problem is a lot of floorlayers will just lay over a old floor an get away with it. Which means they can do a cheaper price. Doin a base screed and dpm will put the cost up a few hundred quid and you might not get the job.
Untill the day that manufactories state that you have to use a approved person to use there products, and that approved person can lose his 'approved' status for doing dodgy work i dont think there is much you can do about that. We need a standard like Corgi/gassafe where you HAVE to be qualified to install XXX make boiler and if they do it wrong or skip corners they will lose there qualification.
I agree Matt, I worked for a crap big firm when I was younger, mixing with a stick, shit screed, cheap glues etc.... But they seamed to get away with it. I want to do every floor the right way so it lasts a long time.
i agree, subfloor prep for things like solid wood is like walking on eggshells. dazlight is right also in the fact that fitters who bosh it, seem to get away with it.
I looked at a job today, pub toilets, quarry tiles on the floor, im thinking about using ardex na and putting down Altro express lay, no adhesive needed and can be laid over damp floors. Sounds to me like an answer to uplifting the old floor or does any1 think different?
Thats a good choice Merit Xpresslay is nice to install done a few just recently, on another note though the first time I was introduced to Everlay when it first came out I had a disscusion with the rep and technical and said if you can make this and make the sheet to go on top why can't you guys come up with a sheet that this Everlay stuff is bonded to however many years later enter Xpresslay think I missed a trick there.
yeah, a fitter i know who buys his supplies from the same place i do. he seen me pick up the leaflet for it and told me it was s*@t stuff. Hes prob RAF.
