How to cast a floor drain and sewage pipe into a slab?

[Anders_Nilsson]

I understand that you should lay the drain pipes before pouring concrete into the form. Now I'm wondering how high you set pipes and drain? We will have drains for the kitchen sink, bathroom sink, and floor drain for the shower. I was thinking the sink and bathroom sink drains could stick up a few cm above the edge of the form.

But what do you do with the floor drain? Do you set the floor drain level with the top of the form and create a slope afterward? I've read about some people who seem to set the drain slightly below to make it easier to create a slope.

How do you prevent the concrete from flowing into the floor drain? Should you tape a piece of casting pipe around the drain? Or tape a round piece of cardboard and pour over it and then knock away the concrete when it has set?

/Anders

 

[Mikael_L]

How do you prevent the concrete from flowing into the floor drain? Should you tape a piece of form tube around the drain? Or tape a round piece of cardboard and pour over it, then chip away the concrete once it's set?

/Anders

What kind of concrete are you using? SKB flows down immediately, so it might be a good idea to have something to hold it back. Otherwise, you should be able to scrape out the drain and slope once it starts to set, at least if the drain is near an edge so you can reach from firm ground.

I poured with semi-flow slump = 4.

I set the flange on the floor drain in the toilet and laundry room about 2-2.5 cm below the finished floor level. The workers were instructed to try to roughly shape a slope there, which they did well, extending quite a bit beyond the drain itself. However, there was a little hiccup. I had cut the drain pipe quite generously, so it could slide 2 cm deeper into the collar. I thought it might be smart to have some room for movement as the Styrofoam deforms and settles over the years. But the concrete guy put his hand on the drain and then his whole body weight to have support when leaning over the concrete surface, so the drain sank to the bottom of the drainage collar. So I had to install 25mm extension rings afterward. I should have secured the drain with this kind of floor drain fixture:

I ran drainage pipes to the kitchen sink and washbasin in the wall. 75 and 50mm collar ends, respectively, with the collar about 10 cm above the finished floor level. The same goes for all the potable water pipes. Now nothing else is "allowed" with potable water.

For the toilet drainage, I let a 110mm smooth end pipe stick up 10-20 cm, which can be cut later once the waterproofing and tiles are laid. The pipe should at least stick up enough so you can apply some waterproofing with the associated collar on the pipe. That is, at least to the top of the tiled floor.

 

[Anders_Nilsson]

What type of concrete are you casting with? SKB just flows right down and then it might be a good idea to have something that dams it up.

I'm casting myself with a tombola, so the concrete's consistency prevents too much flow. I set the well's top a centimeter below the edge of the casting mold and try to roughly level a slope. I tape over the top of the well as splash protection. I should probably do as you did and allow a few centimeters of play. Need to remember not to load the well. The well is only a few decimeters from the edge of the form, so it shouldn't be a problem.

I ran pipes up for the sink and washbasin drains in the wall.
75 and 50mm sleeve ends, the sleeve about 10 cm above the finished floor.
Same with all the tap water pipes. Now nothing else is "allowed" with tap water.

For the toilet drain, I left a 110mm plain end sticking up 10-20 cm, which can be cut off when the waterproof layer and tiles are laid.
The pipe should still stick up enough so you can get a bit of waterproof layer with the accompanying sleeve on the pipe. That is, at least to the top of the tiled floor.

Can you explain how you ran the water hose (PEM?)? Did you drill holes in the sill to fit the hose? I'm going to make a "friggebod" so the insulation will only be 95 standing and 45 lying on the inside.

Isn't it better to cheat and run the PEN hose through the floor in this case? I'm afraid that if I run the hose through the sill, I will only have 20-30 mm of insulation outside the hose because there is no lying insulation on the outside, and then the frost risk is high?

Or perhaps notch the sill on the inside so a PEM 32 hose fits, so you have 60 mm of insulation outside and 45 mm on the inside. How would you have done it? How do you then angle the PEM so it sticks out horizontally from the wall?

/Anders

 

[Mikael_L]

Can you explain how you routed the water hose (PEM?)? Did you drill a hole in the sill to fit the hose? I'm going to build a friggebod so the insulation will only be 95 standing and 45 lying on the inside.

Isn't it better to cheat a little and run the PEN-hose through the floor in this case? I'm afraid that if I run the hose through the sill, I will only have 20-30 mm insulation outside the hose because there is no lying insulation on the outside, and then the frost risk is high?

No, then you can't run the water inside the wall...

I thought it was a regular residential house it was about.

Just incoming water and the water manifold come up through the floor in our case. In these threads, you will find some pictures showing how our incoming water looks; it's a 32mm PEM in from the municipality's water, then two 20mm PEM going out to the garage and friggebod, and then the rest is internal in the house:
http://www.byggahus.se/forum/badrum/180060-smakrad-och-rad-om-klinkerlaeggning.html
http://www.byggahus.se/forum/vaerme-allmaent/163510-inkoppling-vaermepump.html
And also here, but you'll have to scroll a bit.

 

[andersmc]

Can you explain how you laid the water hose (PEM?)? Did you drill holes in the sill to accommodate the hose? I'm going to build a friggebod, so the insulation will only be 95 standing and 45 lying on the inside.

It could very well be that there is too little insulation on the outside of the pipe. It might be safer to run the pipes up through the floor instead.

Or maybe notch out the sill on the inside so a PEM 32 hose fits, so you have 60 mm of insulation outside and 45 mm on the inside. How would you have done it? How do you angle the PEM then so it protrudes horizontally from the wall?

For PEM hoses, fixtures are used to give them a very sharp bend where they go out through the wall.

 

[Anders_Nilsson]

I'm planning to have a kitchenette and a minimal toilet space with a shower at one end, roughly the same size as in an SJ train compartment, known as a "Stockholmsdusch." Perfectly suitable for a small shed.

I plan to bring in the water through the slab under the sink cabinet and install an on-demand water heater, then run the pipes both up to the kitchenette mixer and straight through the wall to the toilet. Plastic mat on the walls and floor. In this case, it might be best to run the pipes through the floor under the sink cabinet to maximize insulation. I'm thinking the shed should have a base heat of +10 all year round so tools and the like don't get damaged.

Can someone explain why water isn't allowed to come in through the floor? Doesn't all water come in through the slab?

What do you think about embedding a PEM50 protective pipe or a cable protection pipe in the floor and then running a PEM 32 through it? Or maybe it's enough to branch off a PEM 20 from the main line to supply the shed? How thick of a PEM do you really need?

/Anders

 

[hempularen]

The well has a cover that should not be removed until the final installation of the waterproofing layer, precisely so that concrete etc. does not flow down.

 

[Mikael_L]

Can someone explain why water should not enter through the floor? Doesn't all water come through the slab?

Should and should not.
That "opinion" is just a derivative of "safe water" and BKR's regulations for wet areas, kind of.

But when building a bathroom, all floor penetrations are risk constructions, so nowadays the penetrations that don't have to be in the floor should instead be in the wall.
And floor drains must be in the floor, and toilets with vertical drains must also be.

You can obviously cheat as much as you want with this, it's in the event of water damage that the insurance company might start to argue, and upon sale, the buyer and/or inspector might condemn the execution and then maybe they won't bid as much for the house.

Now this is just a cabin, so it's probably not particularly serious not to apply all the rules.

 

[Anders_Nilsson]

The well has a cover that should not be removed until the final installation of the waterproofing layer, precisely to ensure that concrete etc. does not spill down.

That's great! That solves that problem.

But when building a bathroom, all floor penetrations are risk constructions, so nowadays you should make the penetrations that don't have to be in the floor in the wall instead.

But where does the water enter a normal house? I understand why you don't want a floor penetration in the bathroom, but assuming that the PEM pipe always comes in through the slab, where should the hole be placed? Can you bring the water into a kitchen cabinet? Or is it standard to always drill a hole in the sill and bring it in that way? Or through the hallway floor and in through the bathroom wall? Or should you build an extra thick wall between the bathroom and the xxx-room to place the pipe there?

As you say, this is a cabin and you don't need to worry, but it's interesting for a "real" house.

/Anders

 

[Mikael_L]

But where does the water enter a normal house? I understand why you wouldn't want a penetration in the bathroom floor, but if we assume that the PEM pipe always enters through the slab, where should the hole be placed? Can you bring in the water through a kitchen cabinet? Or is it standard to always drill a hole in the sill and bring it in that way? Or through the floor in the hallway and in through the wall into the bathroom? Or should you build an extra thick wall between the bathroom and the xxx-room to place the pipe there?

There is no standard. It varies from house to house.

If you checked some of the pictures I linked, you saw that I bring in incoming water through the floor and inside the outer wall in the laundry room.
The laundry room doesn't have as harsh water spraying on walls and floors and doesn't have as high requirements.
But I cast a concrete collar around all pipes going down into the concrete slab to improve the situation for the waterproofing connection. I am not going to spend money on pipe collars for all the pipes, but will instead brush on waterproofing up on the pipes and protective pipes.

 

[Anders_Nilsson]

Ok, I'll have to think about it for the actual residential building.

One more thing, I think it's nicer with a socket end sticking up from the floor for drainage compared to a smooth end. How do you get the styrofoam over the socket end? Or should you align a socket end with the fill level, lay the styrofoam, drill a hole and insert a pipe? Or do you drill a hole that fits the socket and seal it with concrete/foam?

There are double sockets available, but I don't like them, especially for toilets.

/Anders

 

[Mikael_L]

Now you're talking about a house foundation, an insulated concrete slab?

I and most others create the necessary holes.
Then when all the styrofoam is in place, you go over the entire foundation and spray some foam sealant into all the cavities that have formed around pipe penetrations and the like.

 

[Suhagg]

I should have secured the well with a floor drain fixture like this:
[bild]

I fix everything in place with a bit of concrete a day before. Then there's absolutely no risk of anything moving.

It's not easy to keep track of what's happening if you accidentally step on something while wandering around stressed during casting.

 

[Anders_Nilsson]

Now you're talking about a house foundation, that is, an insulated concrete slab?

I and most others create the necessary opening.
Then when all the styrofoam is in place, you go over the entire foundation and spray a little foam sealant into all the cavities that have been formed at pipe penetrations and such.

Yes, we are talking about a house foundation. The "frigga" will be on a slab; the additional cost is negligible for such a small building (3x4.7 meters), and if you think it's too expensive, you can always use form made of "råspont" to save a little compared to form elements. The main reasons, apart from thinking a slab is easier than leveling posts, are that you save building height (maximum 3 meters for the "frigga") and that it becomes easier to move ATVs or other heavy machinery in/out. Additionally, my plot is somewhat marshy since it's located in a local dip, and a slab has less point pressure than posts.

Will probably do as you say and spray foam to seal it. I'll also see if I can find Suhaggs' floor drain fixture.

/Anders