Tile over wooden and concrete floor?

[chriselevate]

Hi,

I've had to rip up and concrete 1/4 of my kitchen floor. The other 3/4 of the floor has chip board over it. The plan is to rip up the chip board, level off the concrete and then tile the whole floor.

What's the best method/practice for doing this? Is it ply across the whole thing? How will if fix to the concrete/wood? What thickness?

Is it going to be cheaper in the long run to go the other way and concrete the remaining 3/4 of the room?

Here's a picture of part of what I'm dealing with:

It's a VERY big kitchen by the way.

Thanks for your help

 

[Richard C]

The problem with tiling over two different substrates is you will get differential movement & even an uncoupling membrane may not prevent cracks appearing where the two meet. Your best bet will be to concrete screed the entire floor & tile directly onto that, you don’t need to lay ply down first.

How big is big? Tile runs greater than around 6 metres generally need expansion joints either central or around the perimeter of the room or, again, you will get cracks developing.

I would also advise you read the Tiling Forum Sticky & Forum Archive posts before doing any work or buying tiling materials, it could prevent you making disastrous & potentially expensive mistakes. It’s important to use only quality trade tilling materials of the correct type for your tiles & tile base; cheapo own brand & DIY stuff is mostly crap.

 

[chriselevate]

Thanks for your help. I would say it's getting on for 6 meters / will have a measure when at home. You say expansion gaps? are these easy to do?

Can you buy ready mixed concrete? Generally how much money do this work out?

Does it need levelling with another product?

Thanks

 

[Richard C]

You say expansion gaps? are these easy to do?

If you just need to allow expansion around the perimeter, leave a gap around the edge of the room much the same as with laminate/hardwood flooring & either cover it with skirting or fill with silicone.

For expansion in the centre of a long tile run you fit these;
http://www.wallsandfloors.co.uk/range/Aluminium-Heavy-Duty-Movement-Joints/

Can you buy ready mixed concrete? Generally how much money do this work out?

You can get ready mix delivered in a mixer lorry but it depends how much you need but they won’t waiting around while you barrow it off & lay it! It’s not particularly cheap either & usually only viable for footings & over site concrete work otherwise it’s a mini mixer & a wheel barrow.

Does it need levelling with another product?

Not if you do it properly.

 

[chriselevate]

Right here's more information - sorry my last reply was lacking the dimensions, I was out of the country so couldn't measure it and internet connection was VERY expensive!!!! lol

The kitchen measures 5.20 x 4.30 and of this space I've already filled 1.90 x 3.60 with ballast (not yet screeded). I would say the depth is 1 - 1.5ft deep.

Am I doing the right thing, hacking the rest of the wood out and pouring the ballast in? Is it advisable to drop another damp proof membrane in before filling? If so, how will it join to the existing one laid? Does it matter if it doesn't join?

Will I need to screed the whole think once all the ballast is in?

How many bags of the ballast would you say I'll need to finish it? (the bags are approx a ton aren't they?)

Thanks

 

[chriselevate]

Right I think I'm going to go for it and concrete the whole floor in - I think given the advice on here it's the best option!

After I've concreted the floor do I apply a 1 1/2" screed over the top?

Can I then tile directly onto the 5.2 x 4.3 meter screeded floor?

Thanks

 

[Richard C]

I assume that’s a cement/ballast oversite & not just a pile of stones! The minimum depth for a conventional sand/cement floor screed is 50mm, you can go less but you will need either a bonded or specialist screed. Are you intending to lay some insulation (i.e. Celotex) above the ballast & below the screed? Both the ballast the screed must be allowed to dry out thoroughly first, which will be at least 4 weeks for the cement to reach full strength but also allow a concurrent 1 day for every 1mm of depth to get rid of the moisture; don’t be tempted to rush it.

You can generally tile straight onto screed providing it’s flat enough (the larger the tiles the more critical) but I would advise an uncoupling membrane below the tiles or you could get a crack along the join.

 

[chriselevate]

In answer to your questions. Not sure I get the joke about cement/ballast?! I'm going to use a 1:5 mix for my ballast.

I'm not intending on laying any insulation.... should I consider this?

You mean I can ballast one day, apply liquid DPM the next morning and then lay the screed on top of this? It'll then take a good 6-8weeks in total to all dry out before tiling yeah?

You would advise an uncoupling membrane below the tile? You mean because a section was concreted at a different time? Does this mean the membrane will need to go over the whole floor?

I'm going to use a 50mm screed over the whole thing though?

Thanks

 

[Richard C]

Insulation will be beneficial & would also reduce the depth of ballast over site needed but will obviously have no effect on the bit that’s already concreted. Given that you have two floor sections which can give problems with differential expansion/movement, have you considered ballasting up the existing floor level & then laying insulated tile backer board over the whole lot rather than a screed? “Marmox” is available in thicknesses up to 50mm & will give the benefits of floor insulation & a stable tile base, removing the need for an uncoupling membrane. You must still allow the ballast sufficient drying time before fixing though.

 

[chriselevate]

Thanks for your reply, appreciate it.

That sounds like a pretty good idea! How does marmox fix to the ballast? This is available in large sheets I guess? What sizes?

My 1/3 that I've laid the ballast in is fairly flat but not perfect, is this a problem?

Can I still paint my floor and lip it onto the walls to make sure NO damp comes through again? I guess once the ballast is fully dry the marmox can go down on top of the ballast ready to tile?

What are benefits of this rather than the screed?

It sounds too good to be true!

Thanks again

 

[Richard C]

Couple of links for you;
http://www.insulationexpress.co.uk/documents/marmox_boards.pdf
http://www.marmox4u.co.uk/manuals/marmoxfloor.pdf

 

[chriselevate]

Richard I'm nearly ready to get stuck in with the ballast at 80mm. Just a few bits that I'm a bit troubled by today....

I've got a few dips in the floor, nothing major just the shape of a brick and maybe an inch down (max). Can I just pop my DPM down and ballast over it rather than having to fill it first. Secondly I've got a few bits sticking up where they've put a but if concrete down to sit the old joists on (a lining of old brittle DPM is stuck to it too. Can I just forget about this too?

And lastly theres a few bits of render missing from the walls, can I just lay the DPM and forget about them too?

Oh one last thing.... where the ballast meets that of the hallway the finish of the hallway edge isn't smooth (it's jagged) shall I paint some synthaprufe on the jagged egde and allow the new ballast to meet it? I've got that in two places actually.

Thanks again.... REALLY appreciate your help.

 

[chriselevate]

Here are some photos of what I've been asking so you can visualise it better.

This one shows the whole thing

This photo shows one of the joins with the hall

This one shows the join with the dinning room. At some point somone has put that concrete in to give an extra strength (I'm guessing this is why they've done this)

This one shows the dips

This one shows the bumps

This one shows the holes in the walls

By the way.... when I lay the new DPM onto the old, do need to attach it or just overlap it? Also... do I need to do antything with the edge that I'm ballasting up to that's already been done?

Thanks again.

 

[Richard C]

I've got a few dips in the floor, nothing major just the shape of a brick and maybe an inch down (max). Can I just pop my DPM down and ballast over it rather than having to fill it first.

The DPM won’t mind the odd undulation but a one inch depressions the size of a brick I’d rough fill first.

Secondly I've got a few bits sticking up where they've put a but if concrete down to sit the old joists on (a lining of old brittle DPM is stuck to it too. Can I just forget about this too?

I can’t really tell how significant or high the bumps are from the picture but if they are of similar size to the depressions, I would level them off; I wouldn’t be too concerned about the old bits of DPM.

You need to get the DPM laying as flat & as close as possible to avoid any creases, rucks forming or voids underneath when you pour the ballast over it.

And lastly theres a few bits of render missing from the walls, can I just lay the DPM and forget about them too?

Should be OK but bring the DPM up the vertical edges of any walls around 50mm higher than floor level & cut it off flush when you’ve laid the ballast.

Oh one last thing.... where the ballast meets that of the hallway the finish of the hallway edge isn't smooth (it's jagged) shall I paint some synthaprufe on the jagged egde and allow the new ballast to meet it? I've got that in two places actually.

I’d slap a couple of coats of Synthapruf on it & bring the new DPM up around half the height.

By the way.... when I lay the new DPM onto the old, do need to attach it or just overlap it?

Overlap it & as above/below, bring the new DPM up vertically around half the height.

Also... do I need to do antything with the edge that I'm ballasting up to that's already been done?

Slap a couple of coats of Synthapruf over it & bring the new DPM up around half the height as before.

Are you pouring over those Speedfit plastic couplings? I don’t like Speedfit full stop or plastic for that matter; personally, I wouldn’t be happy with that. To comply with BS installation & water regulations, plastic fittings and pipe should be removable for possible replacement & Manufacturer’s recommend they be installed in a conduit pipe with access boxes for the fittings.


Similarly, copper pipe should be accessible (mine are in a break out ducts filled with granular Vermiculite) but as a minimum, you should lag the copper pipes with Denso tape or something similar; cement corrodes copper.

 

[chriselevate]

Hi Richard,

I tried to private message you but it looks like I can't.

Firstly... thanks for all your previous help and continued help with this project. You've spotted faults and given me really helpful solutions. Really appreciate this.

Secondly... a few questions. To do the job properly I should be dining the following...

Getting a Corgi gas guy to run the gas pipe and then wrapping it in denso before dropping the ballast? Ideally I should be putting this part into a break out duct with granular vermiculite. Can I ask how to do this please? Is it difficult? I guess with the radiator I can do my own solders and then check for any leaks before denso taping it and then also putting it into a break out duct. Will the radiator copper pipes not expand/contract and burst?

Would you use 50 or 100mm denso tape fir the 15mm pipes and is there a technique for applying it? Does one coat do the trick?

Lastly, an electrician has cone up with a plan for me to take care of the wiring so I can drop the ballast in. He's going to come back at the end and connect the new kitchen ring into the consumer board and check it/sign it off. My question is... how do I run these cables? Through the ballast or under the DPM or how?

Thanks for your time and help.