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Nic B

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Hi all,

My name is Nic and I have signed up to the forum after reading quite a few very helpful threads over the last few weeks.

My question is regarding a Wundafloor UFH system, which I know straight away is going to get a load of negative feedback but I have spoken to Mapei Technical regarding the application of Elastorapid directly to the aluminium layer of the EPS400 board and they have said the following -

We have three options according to type of finish to be installed, ie porcelain, ceramic or natural stone.

Beyond this Mapei have tested those products and methods outlined in order to be able to offer a satisfactory and approved guide to installation.

The chosen method of application lies very much with the installer/ client.

My main question relates to the need for expansion gaps as per BS5385 and whether or not these are required when using the EPS400 system. From what I have read, with a normal installation there should be an expansion gap approximately every 6 or 8m if I remember correctly?

As per the installation instructions I will be leaving a 6mm gap all the way around the perimeter, but the longest run in the room is going to be approximately 10m x 3.5m. It is an L-Shaped room with the lounge being 3.5 x 5 and the kitchen being 5 x 6m approximately.

The Kitchen/Diner is an extension to the existing house and has a concrete base, but the existing house (Lounge) has a standard timber floor.

We will be using 300 x 600 x 10mm Porcelain tiles and Mapei Elastorapid, but nobody seems to be able to tell me if I do in fact require an expansion gap within the 10m run which goes from the front to back of the house.

Sorry for the long post, but any help would be much appreciated.

Thanks again.

Nic
 
O

Old Mod

A floor plan would helpanswer your question. A floor with ufh should have bays of no more than 40m2.
Also, you have two different substrates, these should be separated by an expansion joint.
Both surfaces will expand and contract at different rates
 
OP
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Nic B

TF
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A floor plan would helpanswer your question. A floor with ufh should have bays of no more than 40m2.
Also, you have two different substrates, these should be separated by an expansion joint.
Both surfaces will expand and contract at different rates
Thank you for the response, much appreciated. I will get a floor plan up shortly. I fully get where you are coming from regarding the 2 different substrates and hopefully there is a simple solution. Cheers
 
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Nic B

TF
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Hi All,

I have attached (Hopefully) the downstairs floor plan ad the loopcad drawing which was given to me by the company I bought the system from.

Things have changed slightly since the loopcad drawing was provided for us, we will not actually be running the underfloor heating into the shower room and the island in the kitchen is slightly larger than in the layout drawing.

The Kitchen Diner is a concrete base, as well as the utility room as far as I am aware and the existing house is a timber floor as previoualy explained so the divide where I would think the expansion gap needs to be is where the drawing is showing the steels to be.

Unfortunately I am way too far down the road to change any of this, and the system has already been purchased and delivered so any help on the best way to make this as sound as possible would be appreciated.

Thanks again

Downstairs Floor Plan.png Loopcad Drawing.png
 
O

Old Mod

Is that broken in to 3 zones? 3 colours.
If so, why do you have multiple zones in same space?
Expansion joints should really be used to separate zones. Otherwise you have two different heat sources heating the same part of the floor which can cause problems as it’s unlikely they’ll be exactly the same temp.
That’s what I understand anyway, could be wrong.
Unless someone can advise different.
@Chalker @Uheat - Jake
 
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Nic B

TF
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Forgot to add, the kitchen diners is approximately 6m x 4.5m and the sitting room is around 5m x 3.5 at the wides point...

The instructions say to stick the EPS400 boards to the base, so although I dont see there being much expansion/movement in the boards themselves, I assume the expansion gap would be required because the boards being stuck down would mean they would move with the base as it moves?

Thanks again for the help
 
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Nic B

TF
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Is that broken in to 3 zones? 3 colours.
If so, why do you have multiple zones in same space?
Expansion joints should really be used to separate zones. Otherwise you have two different heat sources heating the same part of the floor which can cause problems as it’s unlikely they’ll be exactly the same temp.
That’s what I understand anyway, could be wrong.
Unless someone can advise different.
@Chalker @Uheat - Jake

The differrent colours are simply to differentiate the different pipe runs, the entire space would be running as a single zone though. I thought this would make more sense with it being a large open space and thought it would cause more problems to have different zones in such a large space
 

Simon Dale

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You should ask @3_fall How many failures he has seen on Wunda Floor. Im sure he would upload images. I as a tiler would not listen to Mapei etc cos when it fails its down to tiler. Never heard of an adhesive manufacturer admitting liability.
 
O

Old Mod

What concerns me is the bridging of different substrates here. Have you fully informed wundafloor of your intentions, do they know you’re crossing from timber to screed?

Simon is quite correct, I was gonna deal with that later, just wanted expansions sorted first.
 
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Nic B

TF
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You should ask @3_fall How many failures he has seen on Wunda Floor. Im sure he would upload images. I as a tiler would not listen to Mapei etc cos when it fails its down to tiler. Never heard of an https://www.tilersforums.com/forums/tile-adhesive/ manufacturer admitting liability.

I have read many of the threads and I am fully aware of the possible issues. I have also read a few threads where people have installed almost identical system without a problem. Unfortunately, as mentioned earlier, I am too far down the road to change it now, nor do I have the money to throw at it to change it all unfortunately so I am just trying to make the best of what is apparently a crappy situation! I appreciate the input though, thanks
 
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Nic B

TF
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What concerns me is the bridging of different substrates here. Have you fully informed wundafloor of your intentions, do they know you’re crossing from timber to screed?

Simon is quite correct, I was gonna deal with that later, just wanted expansions sorted first.

Technically I did not buy the system from Wundafloor direct, but the boards are Wundafloor branded, but I have actually called them to ask about the expansion gap requirement and the lad on the phone didnt have a clue what I was talking about. He basically said that the boards are EPS and wont expand or contract, yet in their literature they say to follow the BS5385 guidelines regarding expansion gaps, so he was clearly clueless, which doesnt fill me with confidence, especially after the nightmare threads I have read which are enough to scare me to death!

which is why I signed up to the forum and asked for help from people with experience. Had I not, I would have just had it tiled and who knows where i would be in 6 months time!
 

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