Master Bath with in floor heating

[Jay C]

As the title states we are in progress of replacing the berber carpet in our master bath with ceramic tile over electric in-floor heating. The heaqting wire requires a 1/4 to 3/8" scratch coat to protect it from the troweling. The manufacturer suggests self leveling cement.

Here is my situation:
I have already removed the carpet and old tile, pulled the toilet, cleaned the are, used deck screws to secure the 3/4" plywood while hammering in any poped nails. I checked the floor for any low spots then applied a 1/4 x 1/4 troweled bed over which I laid 1/4" Hardibacker secured with Rock On screws per James Hardie instuctions.

Now I need to tape the joints, lay the wire, and then apply some sort of scratch coat. I am concerned/unsure about the self leveling cement process. This is an upstairs master bath about 100 sqft. The joists are 2x12 on 12" centers with blocking between some. Can someone who has used SLC give me some pointers. Am I at rikck of overloading my floor with everyting I've installed/will install? The ceramic tiles are 12x12" 1/4" roughly. The SLC I have is Novaplan 2 from Lowes. I am worried about how to provide expansion joints (or even if I need them), how to dam it to keep it from going under walls or do I need to worr about having a 1/4" gap between it and the walls?

Thanks in advance,
Jay

here is a few photos of my progress http://community.webshots.com/album/548054216IlrDZo

[bbcamp]

Welcome, Jay!

You don't have to worry about overloading your floor. If it meets the deflection criteria, you're fine.

[Jay C]

Originally Posted by bbcamp

Welcome, Jay!

You don't have to worry about overloading your floor. If it meets the deflection criteria, you're fine.

Any info on "daming" for SLC? I think that is my biggest concern.

Thanks,
Jay

[bbcamp]

Yeah, I had to run before I could get to that.

You need a 1/4" expansion joint around the perimeter of the room. A foam produce called Sill Seal works well. Simply staple it to the walls, then trim off the excess after the SLC cures. You can caulk the walls before you install the Sill Seal.

You can attach temporary dams made of scrap wood or even duct tape. You tape over the toilet flange and any infloor HVAC registers. Mark their locations, then break out the SLC and remove the duct tape after the SLC cures.

[Jay C]

Excellent, you just reminded me of some fan fold foam I have (used it for making RC airplanes).It's the stuff they put under outdoor siding. Ok, those two makes me feel a bit more confident.

Now, I'm a one-man show. I bought 4 50# bags of the SLC and 4 boxes of primer. I usually mix my mortar/grout in the garage and haul it up stairs ... think I sholuld move the operation to the bathroom to save some precious time? My wife has the full time task of managing our 2-yo.

Thanks again,
Jay

[bbcamp]

I think you should move your operations to near the bathroom. I also think you should con a friend to help. Offer steak and beer.

[Jay C]

Ok, today is the day I pour my SLC. I have 4 5-gal buckets, 1 3gal for the primer. I have 4 50# bags and intend to pour 1/4 to 3/8" (enough to cover my infloor heating wires). Per your suggestion I have put up a foam wall dam around the perimeter with a 1/2" collar around the toilet flange.

I plan to use a short nap mcheapie roller for the primer. The SLC says use a rake? Is this necessary? If so, can I use my notched trowel? That's about it, I'm planning for the best.

Jay

[Jay C]

We didn't pour it. I wanted to read some more before I commited. In my mind it's not just the floor that could be ruined but my investment in heating cables. Here are some photos I have taken to this point.

Anyway after reading about one project I decided to recalculate my area. Oops, I had been using the sqft of the heated space for my estimates (100sqft) when in reality it's 150 sqft. Good thing. I bought 3 more bags of SLC today (7 total) just in case. I also bought some caulk to replace the duct tape and make sure I don't find any leaks

Jay

[jadnashua]

You'll need something bigger than a trowel...depending on the stuff you bought, it could start setting up in 10-minutes or less, if it is hot in the room. You need to be mixing and pouring almost continuously...that's why you need either help, or have everything layed out and measured so there is no delay. The stuff does flow, but it is sort of the consistency of pancake batter. It will go to a feather edge, but it needs a little help to break the surface tension first. If you try to move it around after it starts to set, you'll make a mess. Once the whole area is wet, it will seek its own level and be flat if you get it all poured quick enough.

[sweet48]

hey Jay C, I bought this same heater sytem, and installed it in the shower area with none of the clamping stripps just scratch coated in . it worked pretty well . haven't tiled over yet , My bigesst concern is that they don't want you putting rugs over the top of this . I am planning on spacing the main area @5 inches to try to reuce the heat there and use the sensor in the shower area where it is at 3 inches. . do you have any of the same concerns. this product does seem to be the least expensive of all others on the market. hope we are going in the right direction . looking for advice from anyone

Thanks for listening John

[Jay C]

hey Jay C, I bought this same heater sytem, and installed it in the shower area with none of the clamping stripps just scratch coated in . it worked pretty well . haven't tiled over yet , My bigesst concern is that they don't want you putting rugs over the top of this . I am planning on spacing the main area @5 inches to try to reuce the heat there and use the sensor in the shower area where it is at 3 inches. . do you have any of the same concerns. this product does seem to be the least expensive of all others on the market. hope we are going in the right direction . looking for advice from anyone

No corcerns for me on that one. Yeah this system was 50% the cost of other vendors and actaully (IMHO) eaier to design for since it's a single termination (DFT version) versus the start and end connections scenario.

Per their site "1. Mats or area rugs not thicker than 1/4" may be placed over the finished flooring."

Jay

[Jay C]

You'll need something bigger than a trowel...depending on the stuff you bought, it could start setting up in 10-minutes or less, if it is hot in the room. You need to be mixing and pouring almost continuously...that's why you need either help, or have everything layed out and measured so there is no delay. The stuff does flow, but it is sort of the consistency of pancake batter. It will go to a feather edge, but it needs a little help to break the surface tension first. If you try to move it around after it starts to set, you'll make a mess. Once the whole area is wet, it will seek its own level and be flat if you get it all poured quick enough.

10 minutes is the flow time yes. I have to go to a depth of at least 1/4" to cover the clips holding the wires. We have 6 5gal buckets that will be pre-filled with water. I plan to set up a mixing booth (using drop cloths to create an enclosure) just outside the bathroom door. My wife will mix with a 3/8" drill loaded with a eggbeter mixer. I have 7 50# bags of the leveler from Lowes and 2 gallons of primer.

Now I just need to get over my fear of failure and loss of investment in the CBU, heating wire, and SLC in under and hours should something go way off course (roughly a grand).

Thanks for the information,
Jay

[jdm]

I've never used SLC, but I'll pass on something I read in another thread. The SLC won't self-level until it's level is higher than the heating wires. The wires stop it from flowing. So don't despair if it doesn't seem to flow well at first. Just keep going until you have enough material down.

[kdzgon]

from the website:

Can Warm Tiles cables be installed in showers?

Generally, Warm Tiles cables can be installed in shower areas by installing the cables in a scratch coat using the standard method noted in the installation instructions. Then, a waterproofing membrane is installed over the cables to ensure that all water from the shower is directed to the drain and does not come in contact with the cables.

It seems as if a scratch coat is ok in a shower floor, so I'd guess it would be OK on your floor, too. Sounds like they may recommend slc to avoid accidental damage from a trowel, no?

We installed SunTouch, which is embedded in plastic mats. This looks like it's just the wire and those plastic strips - I guess that makes it more delicate when working with the concrete immediately covering the wires?

You said it was 50% less - may I ask what it cost and how large an area you covered?

Laurie

[Jay C]

It seems as if a scratch coat is ok in a shower floor, so I'd guess it would be OK on your floor, too. Sounds like they may recommend slc to avoid accidental damage from a trowel, no?

A scratch coat would be enough yes, but we are talking 100sqft with wire and another 50sqft without ... 3 days versus 60 minutes is my guesstimate.

If it's not against the rules here (and I'll remove it if it is) I paid $460 for two 190' rolls of wire and a programmable thermostat with sensor.

Jay