Elevated Brick Paver Porch Floor Design 2

[SlideRuleEra]

Today, I have a question. Am designing support for a brick paver floor on a Clients's existing, large, covered, elevated residential porch. Planning on using the Wood Framing Assembly detail from the Brick Institute (BIA), Technical Notes 14B - Brick Floors and Pavements, Part III at this link

http://www.bia.org/html/frmset_thnt.htm

Here is an image of that detail (Fig. 8)

Per BIA recommendations, plan to slope the floor 3/16" per ft. for drainage and, since the paver joints will be mortared, limit deflection to Span/600 (for both the plywood subfloor & the floor joists).

My question concerns anchoring the mortar bed for seismic loading (potentially significant). Dead load of the 2.25" thick brick pavers / mortar bed is about 30 psf. For this application friction between the mortar bed and the felt underlayment seems to be only meaningful restraint to horizontal movement. (There is nothing at the porch outside perimeter to keep the whole brick / mortar assembly from tending to side over the edge).

A possible solution that I have in mind is to space 8d galvanized finishing nails along the length of each floor joist, with the nail heads projecting 3/8" above the felt underlayment. This should give the mortar bed something to "grab hold" of.

Comments and/or alternatives welcome.

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[dik]

You might want to look at using 'stucco wire' as an alternative. The stucco wire could be secured to the sheathing and joists and 'tie down' the mortar bed.

Dik

 

[JAE]

Maybe some California members can weigh in but do the pavers have to be connected here? You could potentially set up an edge condition that would prohibit "sliding off the edge" - but nailing through the felt might allow more moisture to get to the wood and cause more problems in the future with rotting (not that the felt is 100% waterproof) or with nails rusting etc.

Or at the least you could nail some 1/2" wood stock (like 1/2" x 1/2" trim boards) to the top of the felt and use them as wood keys that project into the mortar at occasional intervals and directions.

 

[SlideRuleEra]

Thanks to both dik and JAE for your input. I have learned a lot researching "stucco wire". Stucco is not common in my area - local contractor's could easily misuse it.
The point about the felt "leaking" in this application is well taken. I believe that updating the standard detail by replacing felt with self-sealing W R Grace Ice & Water Shield would be an improvement.

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[boo1]

I have installed simular designs. We used PT subfloor , PT 3/4" plywood, a membrane, then Durarock (or Hardboard). Also consider a latex modified mortor and grout, to allow for the extra movement.