Floor prep..

[dboden]

I have a kitchen floor to do.. 26m
Half is floor boards (solid & sound)
half is concrete..
I was going to glue and screw 6mm hardie boards onto the boards, overlapping the concrete by 50-100mm, then make up the concrete depth with flexi SLC.. does this sound the best way?
Thanks in advance

 

[J Sid]

Needs an expansion joint at intersection of concrete and wood or very likely to get a crack form. You may be lucky and not have any problems but your method is not recommended

 

[dboden]

Ok, good point, thankyou....
What about if I do the above, but with the addition of a metre or so of the anti fracture matting over the joining area!! Surely that will cover everything?

 

[J Sid]

If it was me, I would screw the boards down, don't screw into any pipes etc. prime, Ditra the boards if as good as you say or over board with hardie up to intersection of concrete, self level the concrete or Ditra, depending on condition of floor. Tile, with expansion joint, profile or colour match silicon over intersection of the two substrates.
Boarding across the joint, you may be lucky and get away with it if it was your own home, but for a customer, no, not the thing to do.

 

[dboden]

It is brick bond so that messes with the expansion joint really..
What is you opinion on the anti fracture matting idea??.. Isn't this what its for?

 

[J Sid]

No that is no what its for.
Its for lateral movement, you will get lateral and vertical movement at the joint. The vertical movement will do the damage.
I have seen ply and cement boards crack when what you want to do is tried.
Can the bond be turn the other way?

 

[Rich Midge]

I already know I'm going to be slated for this but this is how I tackle these floors and have covered it in other threads. You want to make sure the boards are solid, flat with no deflection. If this means lifting boards, adding noggins or even building piers then so be it. Ply the prepared boards overlapping the concrete by a good couple of feet. I screw this to the joists and the boards and glue it and screw it to the concrete. This means alot of drilling and alot of plugs! I then slc the concrete up to the height of the ply. On top of this I lay a decoupler over the whole floor. Unconventional, yes, costly, yes but I've even layed chipped edge trav with all its holes and veins successfully this way.

 

[J Sid]

Its a lot of work and expense to do away with the expansion joint. If one did fail, even if very unlikely, you have no comeback on any products used, leaving yourself open to a costly retile

 

[Rich Midge]

Fully aware of that mate. I also make my customers fully aware they're taking a risk. It is amazing what lengths people will go to, to avoid using expansion strips! I'll admit I offer no formal guarantee doing floors this way but most are willing to go with it. As my work is pretty much exclusively recommendations I think people know I'd correct any failures.

 

[J Sid]

I wouldn't slate you for your approach, but would be amazed if other don't.

 

[Stocks Tiles]

Further to the comments been given, if you have a agreement with the customer that if they go ahead it doing it your way with no joint in the difference of floors then you can't guarantee it won't crack and get this is writing! Because that verbal agreement would never have happened if it cracks! :yesnod:

 

[Rich Midge]

There's always got to be a level of trust between worker and client. They have to trust me to do the best job I can (which is in my best interest anyway) and I have to trust that they'll pay on time etc. There's risk in every job you take on.......maybe I've just been lucky! ;-)

 

[J Sid]

A letter from the customer telling you to do it in a manner not recommend by the material manufacturers, trade bodies, British Standards will mean s*** in a court if law, as a professional tradesman you have a responsibility to do the job the correct way.

 

[Rich Midge]

It's in no professional tradesman's interest to do a job incorrectly. I, as a professional wouldn't lay a floor as I outlined earlier, if I didn't believe it would last a lifetime. I, as a regular bloke also have a responsibility to my wife and family so I'm not in a position to walk away from a job over the use of expansion strips. If someone is absolutely adamant they don't want them, then this is the solution I present them with. Really don't think you should question someone's professionalism on the strength of trying to find alternative solutions.

 

[Ian]

Here's a question, if a floor like this was done without an expansion joint, how long would you expect it to be before a crack appeared of one was going to? A week, a year, after any UFH had been turned on?

 

[J Sid]

Rich, I hadn't read your post #12 as it was posted when I was formulating my post #13 which was in response Stocks Tiles post #11 and his comments about a verbal agreement being no good if it goes wrong, implying a written one would be ok.
I did not question your professionalism, I stated what I believe to be correct.
I stated that as professional tradesmen you have a responsibility to do a job the correct way in the eyes of the material manufacturers, governing body and BS
I believe that if a solution to a problem didn't work and there was a recommended way to do it that would have worked, a law court would not take into account a letter from the customer stating to do it the wrong way would stand up.

I loss many jobs each week when 'tilers' claim its fine to tile wet area's on plaster board, untanked, to put large format tiles on plastered plasterboard, tile directly on chipboard floors, to do away with expansion joints, this list goes on. If I have to sit at home because of it, so be it. Yes, I have a family and a mortgage and I would rather be working.

 

[Stocks Tiles]

I didn't say it's ok, I said get it in writing as verbal doesn't exist. Yes standards need to be met but how many customers want what they can't have without paying for all the extra work? At least with a written agreement you have SOME defence if done the work. I wouldn't carry out the work as first stated but it's not for me to say don't do it. I guarantee all my work and this is something I couldn't unless good money is paid to do right (edit: to avoid the expansion joint) and I quote for any works that needs doing regardless of a customer requesting or not, I explain everything in detail and if I don't get it then I don't get it. Hope that helps explains what I was getting at... If not never mind!

 

[J Sid]

Here's a question, if a floor like this was done without an expansion joint, how long would you expect it to be before a crack appeared of one was going to? A week, a year, after any UFH had been turned on?

This job has no ufh, anyway none mentioned.
To many variables to answer.
Ceramic, porcelain or stone?
How much movement / bounce in wooden floor?
How new is the concrete?
Is it a new build?

I've seen floors tiled onto ply with the correct adhesive, apparently, and the tiles have crack along every joint within months,

I've seen job tiled over two different substrates as this post last years.

I'm sure you're seen the same Bri

 

[J Sid]

Stocks

"but its not for me to say don't do it"

If a forum member / member of the public comes on this or any other trade forum and asks a question on a fixing method they propose to use and it is quite clearly no a recognised method to get over said problem, why would you not say anything?
I maybe wrong, and many say I often am, but I thought one or the objectives of these types of forums was to past on knowledge you have and ask for help or advice when you need it.

 

[Stocks Tiles]

You had already given the advice that's why I said further to the comments above, I didn't correct you are imply you are wrong - you are not and my personal opinion is you seem to know your stuff nothing I have seen over the forum or on another page that I would argue with. Don't know why you're trying to pick a argument though, I only advised getting any agreements in writing I had nothing to add to what you advised.

 

[J Sid]

Unlike some I have no intension of picking an argument.
If I misread your post or misunderstood it, which can easily be done, I apologise.
The way I read it was, you were suggesting that getting it in writing, (an unrecommended fixing method) rather than verbally, you would have 'Some defense' if or when it goes wrong.
I take it that is not what you mean.

 

[Ian]

This job has no ufh, anyway none mentioned.
To many variables to answer.
Ceramic, porcelain or stone?
How much movement / bounce in wooden floor?
How new is the concrete?
Is it a new build?

I've seen floors tiled onto ply with the correct adhesive, apparently, and the tiles have crack along every joint within months,

I've seen job tiled over two different substrates as this post last years.

I'm sure you're seen the same Bri

Yeah absolutely, it's a tricky one to call. A bit like tossing a coin, it might last 20 years or it could last 20 days. My personal thought is, if it is over prepped ie, 22mm ply to the joists (with extra noggins), cement board over that with an overlap onto concrete side, slc concrete then ditra over the lot, it stands a fair old chance of surviving I feel.

 

[J Sid]

Agree, it would more than likely no fail, but at what cost.
Say, 15 m2 of ply + 11m2 of self leveling at 15mm to 18mm thick + 26 m2 of uncoupling membrane.
So what, about £800 to £1000 extra labour and materials to not have any expansion joint.

 

[Rich Midge]

Just to clarify my position on this.
I always recommend expansion strips.
If the customer is absolutely adamant they don't want them, I offer the prep discussed as an alternative option. Cost implications etc are always outlined in my estimate.
I cannot guarantee that at some point the floor may fail. This is nothing to do with my workmanship but because this isn't a recognised fixing method the adhesive suppliers etc wouldn't cover it. Again, this is all clearly written in my estimate.
If a customer doesn't want expansion strips and doesn't want to, or can't pay the alternative, I regrettably walk away.
I've yet to have a failure hence why I'm happy to share on here. Anyway, time for another beer in the Spanish sun! Adios amigos!