tile over epdm

[paarlberg]

We built a house a few years ago and had epdm on several porches. Now my wife wants to put tile on said porches. There is about 1/4" (or very close) slope on the porches. They do not leak at the moment.

I know that cement on the epdm is a bad idea, what options do I have? I searched the forum, but now my head is spinning ;-)

[lochrie22]

Not sure what your deck looks like but they do make what is called "Roof Pavers" that are designed to go over EDPM.

Its a pedastal system and it works very well

[jadnashua]

How much height can you accept above the membrane?

Second question, what size and spacing are the joists? The deck may not be strong enough to throw a lot of dead load on top of it.

[paarlberg]

We have about 1.5-2" we can go up at the house side. I would prefer to be less as there are columns/posts built into the floor and will need to work around their bases. I will get pictures of both porches.

The joists are 2x12 (2x10 on one of the decks) on 16" spacing. Both have a span of about 9-10 feet total.

[paarlberg]

See attached pictures of the 2 porches

The top 2 are under a covered area, the other 2 are an open porch.

There is a drip edge covered with epdm on the edges that has a flashing under them to allow water to enter the gutters. Covering the drip edge is also a concern as well. I will get pics of that as well

[paarlberg]

Drip edge, it is kind of hard to see, but it is there. Basically a 2x4 ripped at an angle to have a point and allow the fascia (PVC) and flashing up under it.

I am in Atlanta if that matters for freeze/frost.

I had thought about placing sleepers on top of the epdm, then plywood and a waterproof membrane on that. Then the tile on top of all of that.

[jadnashua]

I'm thinking an unbonded, reinforced mud bed with tile on top. Since you already have a waterproof layer, that might work fine. Somebody that does this a lot may have some better suggestions. That would use up most of your allowable height though as it needs to be nominally at least 1.5" thick before the tile to hold together.

[paarlberg]

Are there any suggestions for a non-ceramic tile option that wouldn't look like poop?

[cx]

Welcome back, David.

Couple questions:

These porches are over occupied space below?

The EPDM roofing was intended to be the wear layer for these decks?

You indicate you have "about 1/4" (or very close) slope on the porches." Is that the total slope over the depth of the porch?

You say you "have about 1.5-2" we can go up at the house side." Is that the total height from the top of the existing deck to the bottom of the threshold of the entry door from the house?

Originally Posted by David

I know that cement on the epdm is a bad idea, what options do I have?

I'm not familiar with any such restriction. Indeed, it is my understanding that one of the advertised features of EPDM roofing is that it is not adversely affected by cementitious mortars.

The ceramic tile industry standards require, for a tile deck over occupied space, that you have a properly sloped (minimum 1/4" per horizontal foot) primary waterproofing membrane (Your EPDM), then some sort of drainage layer, then a reinforced mortar bed of a minimum of 1 1/4" thickness with welded wire mesh in the vertical center, then another optional direct bonded waterproofing membrane, then your tile. The secondary waterproofing membrane would also want to be flashed at the building wall and your railing posts.

I can't see your edge treatment well enough to guess how you would need to treat those areas and the same is true about your railing newel posts.

As you can see, this is something that should have been planned well in advanced and is not always suitable as an afterthought.

There is one other way I'm aware of that would result in less height, but it would require the elimination, or at least the defeat of the existing waterproofing layer.

My opinion; worth price charged.

[paarlberg]

There are finished porches under these decks

It was my initial thought to have the EPDM as a final layer, or a wood floor possibly over it in the future (using sleepers). This was completed about 8 or so years ago.

Over the 9-10' span, there are approximately 2-2.5 inches of fall across the porch. Water runs off on the larger porch without an issue. The smaller is a little slower and possibly just under 2" of fall for 9'.

1.5-2" will leave me about 1-1.5" to the threshold that sits on a brick ledge.

[cx]

Originally Posted by David

1.5-2" will leave me about 1-1.5" to the threshold that sits on a brick ledge.

I like to keep a minimum of 2" there, but you might be able to live with less.

[paarlberg]

I am considering some of these tongue and groove options over sleepers that add a little more slope. These might be the best overall option.

https://www.aeratis.com/porch-flooring/

Thanks

[cx]

How would you propose to fasten the "sleepers" over your waterproof membrane, David?

[jadnashua]

A floating floor might work. Don't have any experience doing this. The flooring in my first floor is all floating...i.e., not attached to anything except itself, but it's level, not sloped.

[paarlberg]

How would you propose to fasten the "sleepers" over your waterproof membrane, David?

I would allow it to float on top without fastening except along the edge boards to the side walls. Once installed, it won't go anywhere due to weight.