I have two jobs with problem floors 1 A ground floor flat around no more than 10 years old where the vinyl i fitted 6 months or so ago has bubbled badly , moisture test reads rh 94 2 A Hallway/w/c in a house where she previously had a lvt fitted some years ago,all the adhesive when mushy, they discovered they had a drainage problem which went under the floor which has been fixed apparently, but I have put a meter on the floor to read 88/90, looking on the internet the house was built around 1955, so presumably no proper dpm. Not sure what to do about this job , she wants vinyl fitted Was thinking of using the mapei turbo k for the flat What would be the procedure for these, do I screed floor first then dpm or dpm first ?? Any advice about either job would be great as not that experienced in these situations Cheers
Dpm the flat then latexplan trade, the 50's house either dig up and relay concrete with proper Dpm or asphalt
you need to leave hygrometer down on both floors to see if it jumps around with the weather change. You need to do this so you can work out if there is a working DPM in both floors. Because the one floor is only 10 years old dont mean that the DPM is working. It could be damaged. However i would be looking for a possible leeking pipe or bridged DPC outside the property. if you find that both have no working dpm (which stands a chance) then Mapei products cant be used. Fball are now saying you can use one of there epoxys. BUT speak direct with them and be careful, Epoxy DPM's dont fail ! Its the subfloor that fails when the epoxy pulls a thin layer up. So if you bare that in mind if your epoxy dpm did come up and it has concrete on the back of it then its teh subfloor that has failed and your liable. Ideally the subfloor should be dug up and replaced to Building Regs.
How am I going to discover that the dpm isnt working The house built in 50,s presumably wouldnt have one anyway ?
if the hygrometer reading is stable to within a few % (temperature will make it move around slightly) then the floor has residual building moister and a surface dpm can be applied. If the hygrometer jumps up by say 10% after rain or drops a far bit when been hot then its picking up rising damp as the moister is entering the slab and changing the reading. It will be delayed normally by a few days but again this is dependent on slab thickness / soil type etc.
Thats great thanks, incidently i phoned up laybond today, because my local wholesaler is advertising their one coat to be suitable over floors without a phisical dpm, and I spoke to a guy and he said yes but would recommend double the coverage , two coats instead of one. I did read your previous post about there get out clause if it fails, but is it worth a shot, because most customers arent going to go to the cost of digging up the floor just to lay a bit of vinyl
I have used laybond for years. I use ardex dpm most of the time now though. But before that the system I did over floors with no dpm under them was- If rough floor or adhesive left on the floor ( Scrape as much glue off as possible ) screed with laybond ultimate. Then 2 coats of one coat membrane Then prime & screed again. Did the same with f.ball, green bag & F75 with no issues too.
