Tilling on a floor with Karndean already on floor & underfloor heating - Tile Advice

[peteablard]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

single part fastflex

Single part fastflex

USE FOR:-
Most types of FLOOR tiles including:

• Ceramics
• Porcelain and fully vitrified tiles
• Mosaics
• Natural Stone including marble
• Slate

Most substrates including:

• Asphalt (suitable grade e.g. flooring)
• Concrete, cement:sand screeds and rendering
• Existing vinyl tiles, unglazed ceramic tiles, quarry tiles, terrazzo and natural stone
• Fibre reinforced cement boards and lightweight tile backer boards
• Tongued and grooved floorboards
• Underfloor heating

some manufacturers also tell you to use PVA, I personally don't trust everything they say. If I'm guaranteeing it then it's done my way......

 

[ythan]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

hang on, no need for all the no-sayers to get so huffy.



my advice to the raylincs is to show copy of this thread to your customer. Give him 2 quotes: one for tiling directly over karndean; and one for taking the karndean all up.

give him your own professional opinion, and then let the customer decide what he/she wants you to do.


then let the forum know what happened next.




don't see how you can wrong.

 

[raylincs]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

hang on, no need for all the no-sayers to get so huffy.



my advice to the raylincs is to show copy of this thread to your customer. Give him 2 quotes: one for tiling directly over karndean; and one for taking the karndean all up.

give him your own professional opinion, and then let the customer decide what he/she wants you to do.


then let the forum know what happened next.




don't see how you can wrong.

Hi ythan
Thanks, that's what I have decided to do, and if they decide to go with leaving the Karndean down, then I will get them to sign and date a quote say they will take resposibility if the tiles fail.
This is the first time I have posted on the Forum, and thank everyone for their input.
I will let you know what happens!

 

[Ajax123]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

Hi ythan
Thanks, that's what I have decided to do, and if they decide to go with leaving the Karndean down, then I will get them to sign and date a quote say they will take resposibility if the tiles fail.
This is the first time I have posted on the Forum, and thank everyone for their input.
I will let you know what happens!

sorry but that don't mean jack in a court...just hope you get away with it and if you don't I hope they don't use my advice...

 

[jwatson]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

Take advise off those qualified.......a little bit of wisdom given to me in my life.
dave has been a tiler since god was a boy, and ajax is the screed pro on the site. Anyone with half a brain would listen to the FREE advice that has been given.
if the customer does not listen, then let some other cowboy do it. not worth losing rep over it

 

[ythan]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

i asked for a description of the possible mode of failure - ie how, where and why is failure predicted to occur.




do any of the no sayers have the technical ability and time to do this?



talk of court action is frankly ridiculous. i'm also taken aback by the apparent lack of respect for customers views/wishes, and also by bully boy tactics.




bal single part fastflex is a great product designed for underfloor heating and a variety of substrates including vinyl.

it's much easier to use than bal 2 part fastflex & costs significantly less. no doubt other manufacturers have similar products.




i wish raylincs and his customer well.

 

[Ajax123]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

i asked for a description of the possible mode of failure - ie how, where and why is failure predicted to occur.




1. do any of the no sayers have the technical ability and time to do this?



2. talk of court action is frankly ridiculous. i'm also taken aback by the apparent lack of respect for customers views/wishes, and also by bully boy tactics.




bal single part fastflex is a great product designed for underfloor heating and a variety of substrates including vinyl.

it's much easier to use than bal 2 part fastflex & costs significantly less. no doubt other manufacturers have similar products.




3. i wish raylincs and his customer well.

1. not lacking ability but deffinitely lacking inclination. There are several potential failures and my main concerns revolve around the "weak screed".

2. If it is wrong and it fails the customer has a legitimate claim against the tiler. if a tiler is happy to put himself in this situation then fair enough. The customer is not always right and having him sign and date a peice of paper to say he takes responsibility is not generally a lawful defence. Worst case it goes to court.

3. Good stuff, that's the spirit

 

[ythan]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

Thanks for your response, Ajax.




I'm happy to give further explanation of my viewpoint.




Regarding uncertainty about the quality of the weak sand/cement bedding. Given that the karndean has remained firmly stuck down, and is showing no signs of damage e.g. no mention of legs of chairs punching into the karndean etc this shows the substrate is stable and completely adequate to take vertical loads.




The floor has underfloor heating so there will be horizontal stresses and strains set up within its depth, as the floor heats up and cools down. As the floor has been in use for some time any cracking, shrinkage etc in the bedding will have mainly already occurred, and the karndean (being elastic) will have helped distribute the stresses such that any cracking in the bedding will be micro cracks.




So I think:

- Leaving the karndean in place may well assist the bal single part fastflex to safely accommodate/distribute thermal stresses and strains through the interface between the stiff solid tiles and the sand/cement bedding.

- Leaving the karndean in place will make the job much easier, cleaner, quicker and successful for raylinc and his customer.




Just one little point, given the tiling is likely to be done in cold weather, it could be a good idea to set the floor temp to say 12/15 degrees to reduce the subsequent thermal stresses when the floor is in normal usage.




All considered comments welcome.

 

[tolola2]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

Hi Raylincs
Karndean needs to come up,if you tile on top whether you use flexi or not the tiles will come away from the karndean.Do the job as it should be done and there wont be any probs
Tolola2

 

[mz30]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

single part fastflex

Single part fastflex

USE FOR:-
Most types of FLOOR tiles including:

• Ceramics
• Porcelain and fully vitrified tiles
• Mosaics
• Natural Stone including marble
• Slate

Most substrates including:

• Asphalt (suitable grade e.g. flooring)
• Concrete, cement:sand screeds and rendering
• Existing vinyl tiles, unglazed ceramic tiles, quarry tiles, terrazzo and natural stone
• Fibre reinforced cement boards and lightweight tile backer boards
• Tongued and grooved floorboards
• Underfloor heating

It doesnt say karndean/vinyl tiles layed on a sand and cement screed with under floor heating ,and thats where the problem would be if a failure occured.

Am not saying its right or wrong to tile on vinyl as a lot of reps around the country would recommend a product to do so and would believe in that product,i will say when asking a rep that they know the exact substrates involved.

 

[ythan]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

mz30 - welcome any comment on my last post above re the sand/cement bedding.

is this a job you'd have simply walked away from?

 

[mz30]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

No i wouldnt walk away until i had all the facts,from what has been posted by the o/p the chance of failure is there but does not mean it will fail,there is a chance on every instalation of failure regardless of measures taken, as tradesmen we have to eliminate as many foreseable problems as possible.

Unfortunately a lot of guys on here put the cart before the horse and say everything they disagree with is destined for failure and then the people reading it think i'll post the same and i'll be right,always a problem with forums.

 

[Martino]

Re: Tilling on a floor with Karndean already on floor & underfloor hea

Jobs like this are fairley simple to me.....give the customer a quote to rip up old and fit new....if they say no.....so be it ....at the end of the day customers WILL always get cheaper!.......BEER money some people work for these days and these are customers u dont want!

 

[raylincs]

Hi All
I thought I would post an update.
After speaking to the builder who built the customers extension, the Screed isn't weak, a misunderstanding by the customer.

I have spoken and have an email from the Tech Dept of Kerakoll Adhesives and given them all the info regarding this job and they have reconmmended and confirmed that I should:
Clean & dry the floor, use Keragrip Eco Primer, and then affix the Porcelain Tiles with Marmorex Adhesive, Grout with either Fugalite Eco Grout (never stain/shade etc 2part) or Fugabella Eco 0-5 (cement based grout).

Many thanks for all the replies.

 

[ythan]

never used kerakoll marmorex so i'll be interested to hear how you get on. i guess it must be similar to bal's single part fastflex but maybe lower cost?