OK I priced a job for 90 sqm of van Gogh and was told there was underfloor heating in the garage conversion fine! So I've installed all the rest on 18 mm ply thinking there was no Ufh with Karndean PS only to be told there's Ufh through out. So I've googled bits as I was going to use 46 in the garage and Karndean PS isn't really a PS so really pooin myself. The Ufh is off but its there only heating source with only little heaters going so not very warm. I've told them to turn the heating up 1 degree a day but am I thinking right that the worst that could happen is it will tent and I'll have to trim and restick with 46 ? Not using Karndean adhesive again. Only brought it as it was on promo.
Lets hope you didnt go through any of the UFH screwing the ply down!!! I never bother with the Karndean adhesive, I just never get on with it. Are the planks bevelled edges? (Just thinking ahead when or if you have to retrim) I always use the Mapei HT adhesive now, hate f48 as I find it rubbish lately.
I didn't fit the 18 mm the builder did so not worried on that score. Yes bevelled edges again not to much of an issue. I use 46 over Ufh as fball say its OK.
Would Balls hold there hands up if it starts gapping? Better off using the glue the flooring manufacturer specs just to cover yourself
i hope so as they say it can go over Ufh!! I don't like Karndean ht as it sets to quick so wouldn't have used that anyway it would have been 46 but had the tub of Karndean PS thinking it was a PS adhesive. I think worst case it will pop and tent and I'll have to glue and trim.
hopefully it will tent on the weakest plank so only one plank will need to be trimmed, if F46 / Mapei PS 99% of the time. I have never pushed karndean / uzin ps to see what happens with heat yet so dont know. Your guinnea pig!
I've used 46 once in underfloor heating It's didnt go to well and I had to trim a bunch of planks. This was into a gyvlon floor and seemed very warm. I always get put off when it says "normal underfloor heating". What's normal? Never had the guts to try it again :s
problem is the customers dont treat the UFH correctly. The subfloor should never really drop temp below normal living temps. So lets say thats 21c ? (So your issue should be it shrinking in summer when heating shut down and subfloor temps dropping to maybe 16c ish ? not tenting through to much heat ) So lets say that in winter that the underfloor heating has to run at its max (27c) . Thats around a 6c increase. This will give approx a 0.5mm growth per plank per meter in length. This will normally be absorbed into tighter joints and will remain sitting flat. Worse case will be a plank per row might pop up if getting to hot like a rug on top of floor maybe? (im refering to a PS adhesive here, most wet sets, HT etc have really good upwards grab and will actually crush the ends of lvt before they let go giving a tenting effect but still bonded to subfloor that can not be trimmed etc = destroyed) So if your getting tenting on UFH, well this will indicate the plank was installed at to cold a temp, that being strainght off the van or acclimatised in a room to cold maybe? Maybe it was acclimatised in a room with UFH but underfloor heating turned off lowering temps in room? (yes manufacturers advice turning it off LOL, amazing how little they know about there own products) if it was acclimatised to "normal" living temps (21c) and i mean the actuall lvt needs to be at this temp then you will be fine.
Just found this thread guys. I've exactly the same problem. Installed Karndean on F46 over ufh. Room temp was 19 degrees. I didn't want to use the Universal Acrylic Karndean supplied as It drys to quick etc. So I used F46. Looked great when I finished. Customer put ufh on that night ! Lots of tenting tiles now. I'm getting the blame for using the wrong glue when I know full well it'd have been worse with the Acrylic and it's their fault for switching the ufh on ! Help
should of used the universal and dry fitted and wet set them in, best method for using wet set glue, with the ufh heating if its tented that bad from 19 degrees find out how high they put it up to, max is 27 degrees obviously but id tell them 25 degrees max but not to go above 24 that way you might if lucky get away with it as your talking a 5/6 degree shift from fitted temp, otherwise its uplift and refit probably
No I just find with dry fitting around certain fiddly areas even putting the glue down after by time you lay it all back in I've been having certain areas go off too much not leaving a decent tack or transfer. Never had problems with F46 before so used that like a plank before checking about ufh. Of course Ball say F46 is fine for Ufh and I suspect had I done it correctly and used the Karndean glue the floor would be even worse once they put the heating on. Live and learn I'm never ever going to use my judgment on glue. I'm sticking to manufacturer specifications as it's just too much of a risk.
F46 is no more than a tackifier I dry fit with Karndean universal which is Uzin ke66 Every day no problems It's the strongest adhesive on the market
