Use leveling compound, or just tile it?

[Gareth96]

I'm working on turning my chimney chase into an alcove.. I don't need thermal hearth protection for my stove (BK Princess) so I'm going with hardibacker (already bought it) and tile. Now that I have the old hearth stone up I see that the floor is a bit off level front to back. It looks like the back of the chimney chase is about 1/2" lower than the main floor as if the chase 'sunk/warped' a little. The level is fine left to right.

This shows the floor level left to right in the alcove.

and here's what it looks like front to back..

You can see it's a gradual drop as you go back.

So, I'm wondering if I can just use 6" tiles in the area of the hump since it's very gradual? Or should I use a bit of self leveling compound in there before I put the hardibacker down?

 

[johneh]

Level it you will be sorry if you don't
When I worked in the building trade my boss stressed
DO IT RIGHT if the bones are good the rest will be good

 

[ironpony]

it will be easy enough to fix now. when you put down your thinset for the hardi backer, put a little extra in the back and level the board. the hump will show on your tile lines, the gaps change as you go over bumps. it might not show much in a small area but on a larger job the error grows.

 

[Gareth96]

Thanks.. This will actually be my first try at tiling.. So what you're saying is just use more thinset vs pouring some leveling compound on and letting that harden first?

 

[Gareth96]

I just stuck some shims under the level (by level I mean more 'flat'..) and it seems like the back of the alcove is about 5/16" under the rest of the floor. The alcove is 26" deep, and at 13" in, I need about 5/32" of shims. So it's a pretty consistent drop. Can I make up that much space with thinset?

 

[webby3650]

I just stuck some shims under the level (by level I mean more 'flat'..) and it seems like the back of the alcove is about 5/16" under the rest of the floor. The alcove is 26" deep, and at 13" in, I need about 5/32" of shims. So it's a pretty consistent drop. Can I make up that much space with thinset?

You need to use thinset under the backer board. Start in the back with a thicker bed and work your way to the front. You can get it all laid out with your notched trowel and double check it with a level before you set the board in it.

 

[Gareth96]

Sweet, thanks. That sounds a lot easier than I was envisioning with trying to pour something in to level it out.

 

[webby3650]

Just make sure your thin set is mixed to the right consistency and use the screws that are made for the backer you choose. I think most call for them to be Installed in a 6"x6" grid.

 

[Gareth96]

Thanks again.. I'm glad you said to get the screws made for hardi-backer.. I did buy those and felt like I was falling for a marketing trick I guess the next question is should I use modified or unmodified thinset? The alcove is 26"X48", and outside the alcove is another 25"X68" area. So kind of T-shaped.

 

[Jonathan70]

Use a modified Thinset... Laticrete 253 gold is good , Laticrete 254 Platinum is best... or Mapei ultra flex 2.... Avoid Custom products if you can.....not worth the hassle...use the grout additive called Grout Once as well... Use liquid instead of water

 

[Highbeam]

I don't know guys, wont the extra thinset just spooge out as you tighten the bazillion screws? And you need those screws tight s o they don't boof your notch troweling. I agree to fix it but i would do it with a thin coat of level thinset and let it harden before setting the durock.

 

[Jonathan70]

Couple things: make your mix on the stiff side , not too loose , but trowable & don't screw in the area of excessive build up.... The modified Thinset will form it's own mechanical bond between the plywood subfloor & CBU.

Or just buy a bag of Mapei ultra plan M 20 self leveling or laicrete latilevel...... Prime the plywood, let it tack up mix & pour ..... Tile right on self leveling ..... No need for any CBU then.... Mapei allows you to set tile in 4 hours.... I've done 1,000's of sqft this way ... No problems.... Just follow specs .....tried attaching data sheet ... Don't think it worked..(broken image removed)
(broken image removed)

 

[ironpony]

I don't know guys, wont the extra thinset just spooge out as you tighten the bazillion screws? And you need those screws tight s o they don't boof your notch troweling. I agree to fix it but i would do it with a thin coat of level thinset and let it harden before setting the durock.

Can you define "spooge" as used above^^^. If it is meaning what I think you mean, yes you are correct. Would "boof" mean the same as botched??

 

[ironpony]

also, is that alcove a bump out on the house?? if it is I would be concerned as to why it sagged. If it sags anymore after tiling you are going to wind up with cracked tile along that line.

 

[Gareth96]

It is a bump on the house.. but there aren't any cracks in the foundation, so that droop must have been there from the start. Guess my plan is just to goop extra thinset on and screw it enough to keep the spooging down.. use my level.. and hope I don't boof it....

 

[Highbeam]

Can you define "spooge" as used above^^^. If it is meaning what I think you mean, yes you are correct. Would "boof" mean the same as botched??

Spooge as a verb is when a very viscous liquid is expelled from a confined space due to hydraulic pressure. Sometimes in spurts but sometimes in a steady stream depending on the nature of the hydraulic force acting on the liquid. As a noun it has a separate meaning.

Boof and botch are synonyms.

I should write a dictionary of construction terms.

 

[Highbeam]

Don't they have spooge in Ohio?

 

[DIrtyJersey]

Can you access underneath of it? If so. You might be able to jack up the floor and level it.

 

[valley ranch]

Hi, You've got a bunch of suggestions there. Here's one: In the low area, screw in dry wall screws so that when the level is set on that end, it is level. { as in your last picture] Do this across, with screws in the low area. when you spread the Stiff Thinset fill as high as the screws. You're putting concrete board on top of that I believe I read. Or you can tack those shims down and fill to them as you would to nails. There won't be any thin set except in the low area, it won't go anywhere when you put the creteboard on top, just don't stand on it right away, see that it's level, give it some time then screw it down. Next sit down and have a large brandy.

Richard

Me thinks, Boof and botch are actions that negatively effect the outcome.

 

[ironpony]

Don't they have spooge in Ohio?

yes we do, our ground I very prone to spooge. I learned something today................I will have to figure out how to work this in at the weekly update meeting.

I would have to say it is a regional thing, when I came to Ohio from Long Island a lot of the terminology was different.

 

[Gareth96]

I like the idea of putting screws in the plywood to the level of .. level.. and then filling up to the screws with thinset.. I'm guessing one every 6" would be good, in a grid? Maybe even back butter the hardibacker to get good stick?

 

[valley ranch]

Just screwing the hardibacker down good should be plenty, that's how I've done it. Concrete board doesn't tend to get wobbly or squeak.

Richard

 

[woodgeek]

if this was the Can, I would have an educational South Park clip for you guys.

 

[Highbeam]

As you might imagine, I love southpark.

 

[Ncountry]

I have placed slats(ripped to the proper thickness) every 16" to level, in cases like this. Trowel on the thinset and then screw to slats. After an hour or 2 the thinset will be set-up enough, that you can finish screwing down the board without the mortar spoogeing? out..