View Full Version : Shower Curb / Custom Shower Questions
08-29-2011, 07:05 PM
1. When building a shower curb on a concrete slab I have opted to go the brick route as opposed to the 2x4 route. I understand how to affix the bricks to the slab, however I haven't been able to find a solid answer on what I am supposed to use to affix the vinyl water barrier to the outside of the curb (bricks) as well as the metal lathe used to form the curb over top of the vinyl.
2. Also on a concrete subfloor, do I need to lay down tar paper / metal lathe to give the pre-slope something to grab onto? If so, what is the proper way to secure these two items to the concrete? I've also read that you can just use thinset to have the existing slab bond to the pre-slope.
Appreciate the help in advance!
08-29-2011, 08:10 PM
Well, on question 2, either put down some thinset or make a slurry of portland cement before you throw down the deckmud. Make sure you cover it before it skins over. On a slab, you want it bonded, and either of those will bond it in place. If it was on a wooden slab, then you'd want something to prevent the wooden deck from sucking the moisture out of the deckmud before it had a chance to cure...not the case on a slab.
If you overbend the lath for the curb, it will act like a spring clamp. Be careful not to tear the liner when you put it over the curb. Then, you cover it with a sticky brick mortar. A good place for reference material on shower building and anything tiled is www.johnbridge.com (http://www.johnbridge.com). Look in their 'Liberry' section.
08-30-2011, 06:59 AM
Shower Curb / Custom Shower Questions
1. When building a shower curb on a concrete slab I have opted to go the brick route as opposed to the 2x4 route.
Good for you. Wood has no business in our shower curbs. Too often a failed job stems right from this material selection.
I understand how to affix the bricks to the slab, however I haven't been able to find a solid answer on what I am supposed to use to affix the vinyl water barrier to the outside of the curb (bricks) as well as the metal lathe used to form the curb over top of the vinyl.
Like Jim mentions. Bend the lath and mud it in place. Here in Vancouver I'm a huge fan of Mapecum Pre-Mix fast setting screed mortar. The face of the curb does not need to be wrapped with the liner. Just the inside and the top. You might consider using Nobel TS instead of the regular linear. Nobel TS is as thick as your liner but it can also be set in with thin set. Nobel TS is far more durable than Kerdi and very easy to work with. You can look at how to build a Nobel Shower here - How to install Nobel TS Waterproofing (http://www.noblecompany.com/Portals/0/PRODUCT%20INFO/Installation%20Instructions/NobleSeal%20TS%20Installation%20Instructions%20-%20ENG%201208.pdf)
2. Also on a concrete subfloor, do I need to lay down tar paper / metal lathe to give the pre-slope something to grab onto?
Over concrete the concrete needs to be sound and clean if you are bonding directly to it. We like to clean it well with a diamond encrusted block so we can remove any debris fast and easily. This tool also scratches the surface. In a perfect world you would shot blast your slab. We have had good success with a slurry coat of Mapecum Pre-Mix mixed with the liquid from Mapei (Planicrete). Over this slurry coat the Pre-Mix product.
If so, what is the proper way to secure these two items to the concrete?
Tar Paper works as a slip joint and is used mostly in wooden construction. Roofing nails pin down the diamond lath if the lath is placed low but ideally the lat is placed mid span of the pre-slope so you place your concrete add the lath and then place more concrete. The weight of the concrete holds the lath in place.
I've also read that you can just use thinset to have the existing slab bond to the pre-slope.
The cure times need to be the same. Safer to use a product like Mapei's Screed Mortar and a slurry coat.
How much tile work have you done before? Have you the right tools to mix up dry pack or thin-set? Mixing concrete, thin-set, grouts and the lot is Science. The mix ratio's an exact chemistry ratio. Read the bags your working with. Look for the safety data sheets. Measure your water. An use the proper drill. If the plan is to use that 14.4 volt cordless drill in the shop - come up with a new plan.
08-30-2011, 07:05 AM
Building a code require pre-slope
Here is a good review for you. This is a standard install. Watch how the corners are done and where the liner goes into the walls.
Some Nobel TS installation instructions.