Wundatherm UFH Ultra Floor Level It Two cracking

Hi,

My flooring guy adhered to all the advice from the Wundatherm folk about using the right primer and products to prep and latex over the Wundatherm XPS boards, but still we're getting a lot of cracks along where the edges of the boards were.

Unsure if this is a total disaster, or if recoverable. Floor was laid 2 weeks ago and flooring guy said to ensure UFH is fully working for 2 weeks so he can inspect if anything has changed. I'm super worried now that this will cost a lot of money to fix.

Any thoughts on what you see?

 

BTW, this section is new extension block and beam up to current building specs.

 

Wrong screed used imo.

 

Possibly crack bridge all the cracks, then go over with a fibre screed

 

Awful stuff, these ufh manufacturers have no idea. They all must have a big commission from ultra because most of them spec it.

I would have used good old fibre based renovation or ardex

 

How did you introduce the ufh?

 

Not been turned on yet and latex was laid 12 days ago.

 

What’s the correct procedure to bridge the cracks?

 

I wouldn’t bond anything to these systems.

 

Just seem to always be issues with preps cracking & blowing with these systems.

I literally prime the death out of them and flood it with renovation minimum 12mm but usually ends up more like 15mm+

Defo don't use any of the ultra floor screeds on them anymore. Did do a couple because the customer was adamant but just don't like their screeds, inconsistent mixes I found

 

What i did notice is the foil boards just don't feel dense enough

 

Hate going over ufh,prepared one this week, 30sqm ,floor up and down all over the place, whole floor on a bit of a slope, height restrictions in parts, screeded 3 times,used 36 bags of renovation

 

The systems are easy if followed correctly, trouble with most ufh suppliers it’s all about price so ultra wins, there’s systems out there that work and are easier to follow, bonding the xps down correctly is usually the first problem, ms adhesive them down and then ideally use a bag and bottle, less stress and will work better over foil based xps systems with s good prime first, min 10-12mm depth thrown in for good measure unless it’s a cement routed board and then it can be as low as 7mm

 

Hi Adam,
Do you have a recommendation for the type of adhesive to be used when bonding EPS boards to be bonded to floor slc'd with mapei ultrapan. Between the quotes I got for UFH, only wunda have recommended and costed for a rapid bond spray adhesive. Also, the bag and bottle reference in your post, has got me head scratching, what does it mean?

 

Part Latex levelling compound instead of part water based

 

Ahh ok. Thanks. A bit too late for me on that because I have already used Mapei renovation screed on most of the floor. One for the future though. Any recommendations on EPS adhesive other those recommended by the likes of Wunda etc?

 

I would use what they recommend incase you have any issues

 

I’d use a ms adhesive, flexy fix or equivalent, bag n bottle is a latex and compound optional so a compound that’s mixed with latex and not water, they usually allow for more flex

 

Thanks Merit and Adam. I already had bags of Mapei renovation screed.so just have got by using them. I see what you mean by flex, because on the product I used, I have noticed hairline cracks when the floor surfaces meet at right angles to each other. For the adhesive I shall ask the question to the ufh supplier w.r.t warranty etc.