I'm planning to lay EPS concrete in the bathroom. It's a total of about 12 cm to be filled, but I'm thinking of using 10 cm of EPS and the rest with self-leveling compound with underfloor heating in it. Is 2 cm enough for the leveling compound, or should it be thicker?
I've seen on YouTube that they mixed the EPS concrete in a trash bag to avoid dust. Does that method work?
I'll probably have trouble applying the leveling compound within 3 days. Is it enough to cover everything with plastic to buy more time? How much more time will that give me? Or is there another way to get more time? Applying primer?
I've seen on YouTube that they mixed the EPS concrete in a trash bag to avoid dust. Does that method work?
I'll probably have trouble applying the leveling compound within 3 days. Is it enough to cover everything with plastic to buy more time? How much more time will that give me? Or is there another way to get more time? Applying primer?
surris
Construction veteran
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surris
Construction veteran
- Sverige
- 1,467 posts
What do you mean by buying more time?S stefand said:
Is it water-based or electric underfloor heating? If it's electric, you’re fine with 20 mm, but if you need a slope, remember that it needs to be 15-20 mm at the thinnest point.
Buying more time means I might have 2 weeks to lay the self-leveling compound instead of a maximum of 3 days.
It is an electric floor heating. It would then be 20 mm from the EPS to the edge of the drain. So it will be higher at the walls so I get a good slope.
It is an electric floor heating. It would then be 20 mm from the EPS to the edge of the drain. So it will be higher at the walls so I get a good slope.
surris
Construction veteran
· Sverige
· 1 467 posts
surris
Construction veteran
- Sverige
- 1,467 posts
Okay, I've never used EPS concrete, but do you mean you need to apply the leveling compound no more than 3 days later due to drying out?S stefand said:
Yes, with plastic and by moistening the slab, you delay the drying process; that works well with regular poured slabs. I don't know exactly what properties this concrete has. I would try to plan so it can be done according to the recommendation.
When I redid our bathroom, it took just over 6 months from EPS until we applied filler. We had primed, and it remained unchanged the entire time. So prime and possibly cover with plastic if you want to be sure, and you'll have all the time in the world.
I wouldn't mix EPS in a garbage bag. Buy a large tub or barrel at Biltema and use a classic whisk for smooth mixing. Just make sure to have a reasonably powerful drill for the whisk, as it's a bit heavy for the machine to mix.
A tip is to spend a little effort on setting up guide tracks. You won't be able to level it by hand; guide tracks are a must.
How thick the self-leveling compound needs to be depends on the manufacturer. Read their installation instructions and follow them accordingly. We have water-based underfloor heating and needed around 20mm over the pipes to get it right (I don't remember exactly now). If you're going to have a floor drain, you need to account for having the right overlay closest to the drain and thicker farther away due to the slope. Calculate this so that the compound doesn't need to rise above the threshold just because the door is far from the floor drain.
I wouldn't mix EPS in a garbage bag. Buy a large tub or barrel at Biltema and use a classic whisk for smooth mixing. Just make sure to have a reasonably powerful drill for the whisk, as it's a bit heavy for the machine to mix.
A tip is to spend a little effort on setting up guide tracks. You won't be able to level it by hand; guide tracks are a must.
How thick the self-leveling compound needs to be depends on the manufacturer. Read their installation instructions and follow them accordingly. We have water-based underfloor heating and needed around 20mm over the pipes to get it right (I don't remember exactly now). If you're going to have a floor drain, you need to account for having the right overlay closest to the drain and thicker farther away due to the slope. Calculate this so that the compound doesn't need to rise above the threshold just because the door is far from the floor drain.
If it's not a large amount, it works to mix in garbage bags 
depending on the type of floor heating. I usually set the laser at the correct level from the height of the floor drain, which will be the lowest point with the self-leveling compound later, then I empty bag by bag and distribute it with a wide putty knife. Make sure to keep the height to the laser approximately; it's not millimeter work since you'll be leveling later, but you want it smooth and nice so it's easy to lay the floor heating afterward.
depending on the type of floor heating. I usually set the laser at the correct level from the height of the floor drain, which will be the lowest point with the self-leveling compound later, then I empty bag by bag and distribute it with a wide putty knife. Make sure to keep the height to the laser approximately; it's not millimeter work since you'll be leveling later, but you want it smooth and nice so it's easy to lay the floor heating afterward.
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I just wanted to clarify that I didn't mean to make falls in the EPS with the screeding guides. On the contrary, I meant that you should have them to get it level.
If you have a laser, it's certainly possible to measure against it and keep everything reasonably even. For me, who had never done anything similar before, using screeding guides and a straightedge was very reassuring and simple.
Regarding the floor drain, I secured mine with a dollop of regular coarse concrete before placing EPS. It's probably possible to secure it solely with EPS, but it's reassuring to have it firmly fixed exactly where you want it in advance, so you don't have to worry.
If you have a laser, it's certainly possible to measure against it and keep everything reasonably even. For me, who had never done anything similar before, using screeding guides and a straightedge was very reassuring and simple.
Regarding the floor drain, I secured mine with a dollop of regular coarse concrete before placing EPS. It's probably possible to secure it solely with EPS, but it's reassuring to have it firmly fixed exactly where you want it in advance, so you don't have to worry.
I usually take studs at the right height such as 45x95, about 100-130cm long.
Place one 20-30cm from a wall and the other 40-50cm from the first stud.
Then fill between the studs and pull them back a bit and fill the holes where the studs were.
Then it's just a matter of working your way back until you're done.
If the floor is fairly even, it works well. If it's very uneven, a laser is good; otherwise, use pull-out tracks, but they should be removed and the holes/grooves should be re-cast.
Place one 20-30cm from a wall and the other 40-50cm from the first stud.
Then fill between the studs and pull them back a bit and fill the holes where the studs were.
Then it's just a matter of working your way back until you're done.
If the floor is fairly even, it works well. If it's very uneven, a laser is good; otherwise, use pull-out tracks, but they should be removed and the holes/grooves should be re-cast.
You should always wrap wood in plastic so that the EPS doesn't come into direct contact with the wood. The wood absorbs moisture from the EPS, causing it to dry too quickly. I've used some softer type of plastic from Biltema that is usually used as floor protection during painting (this one). If it can protect floors from paint, it should be tight enough for the moisture to stay on the right side. The advantage compared to construction plastic is that it is much softer and more pliable, making it easy to shape and attach in corners and nooks.
In my bathroom, I created screed rails by casting two steel pipes at the correct height. My father had the pipes on his "good-to-have" shelf, so it was a simple solution. In our small WC, I attached battens to the walls, which I scraped against. These battens stayed in place afterward with the reasoning that you can cast EPS in the stud bays up to the height of the battens and then float over the whole package.
Edit:
We have a very uneven subfloor, so it's not possible to have loose screed rails as nino suggests. If it's possible to have loose screed rails that you can move along with you, it's a convenient solution that saves some time.
In my bathroom, I created screed rails by casting two steel pipes at the correct height. My father had the pipes on his "good-to-have" shelf, so it was a simple solution. In our small WC, I attached battens to the walls, which I scraped against. These battens stayed in place afterward with the reasoning that you can cast EPS in the stud bays up to the height of the battens and then float over the whole package.
Edit:
We have a very uneven subfloor, so it's not possible to have loose screed rails as nino suggests. If it's possible to have loose screed rails that you can move along with you, it's a convenient solution that saves some time.
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