I’m designing a curbless shower in a tiny bathroom for a client and would like to use Schluter’s Kerdi-Line low profile linear floor drain. Problem: I can only achieve a slope of 1-5/8″ as the shower width is only 38-3/8″. Does this give me enough drainage slope? Or should I consider droping the floor of the shower? Any advice will be very appreciated!
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first things first
IMO comfort and utility come before feasability or durability. I can tell from your section elevation that the shower your designing is going to be very uncomfortable to stand in. I think you should consider other options.
Floor Slope for Small Shower
Thanks Deadnuts. It's definitely a challenging space. Appreciate the reply.
1/4" to the foot is plenty of
1/4" to the foot is plenty of slope for a shower floor, so long as you keep it reasonably flat so there are no pools. You want to keep slope to a minimum for standing comfort.
Floor Slope for Small Shower
Thanks Dan H. I'll make that change. Appreciate the reply.
There was a recent article in FHB where a guy used teak or some such wood over a sloped shower floor. Looked pretty cool (asian inspired). Not sure if your aesthetic can handle that, but it's an option if you decide you need a more severe slope.
https://www.finehomebuilding.com/item/31653/a-bath-where-east-meets-west
Floor Slope for Small Shower
That's beautiful! It's not this client's aesthetic but I'll bookmark it as an idea for future clients. Really cool. Thanks for the reply!
I agree that 1/2'' per ft is plenty, i would more than likely opt for less slope on such a tight space.
Floor Slope for Small Shower
Thanks Mark122. It's good to have confirmation. I do think I'll opt for 1/4" per foot. Appreciate the reply.
Can you mud the whole thing?
In addition to the requirement that the slope be between 1/4" and 1/2" per foot, there is a code requirement for you to have a 2" minimum vertical between the curb and the shower drain.
For curbless, you're sort of in a pickle. With linear drains, you can sometimes get an exception from your AHJ from the 2" standing water rule because the likelihood of a linear drain grate being competely covered/clogged is pretty remote. Have a conversation with your AHJ for a work-a-round. If you get a variance, certainly get the design signed off. They're much more up on linear drains than they were 5 or 10 years ago.
I have had the following approved. It's a drawing from another post, so it's not to scale for your shower. Essentially it's a sloped floor with a trench built from deck mud and covered with a topical membrane, then tiled. It entails the plane of the main shower floor being sloped at 1/4" per foot, that'll give you a 3/4" drop with your 3' run. That plane then drains into a trench that is also sloped to a center drain. Within the trench, your drain would have to be 1-1/4" below the edge of the shower floor.
In some showers the trench can be open. In others, it can be covered by a grate. Metal, teak, etc.
The attached design was for a few large showers where a manufactured linear drain wont fit. It's simply a sloped shower floor and a trench shaped out of mud. Don't know if it adds anything to the conversation, but what the heck. Here you go anyway.
Good luck!
Shower Slope
Thanks Mongo! That's a really interesting approach. I'll mention this to my clients as an option. I really appreciate the time you took to reply!