Newbie Looking For Advice on Expansion Gaps With UFH System

[Nic B]

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

 

[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

 

[Simon Dale]

Dont use Wunda Floor please !!

 

[GoneGuy]

Welcome to the forum
As @3_fall said, put a floor plan up so everyone can see and advise you

 

[Nic B]

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

 

[Nic B]

Welcome to the forum
As @3_fall said, put a floor plan up so everyone can see and advise you

Thanks for the welcome, floor plan to follow shortly

 

[Nic B]

Dont use Wunda Floor please !!

Have you had any personal experience with the system? Would love to know why you are immediately against it? Cheers

 

[Nic B]

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

 

[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

 

[Nic B]

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