I was all set to build a water table (drip cap) for my enclosed porch which will eventually get FC siding. Enclosed porch has 4″ concrete floor over crawl space and extends a few inches over block wall. Did search on both subject areas (water table, GP Prime Trim) and became convinced that this would be “best” material to use.
Unfortunately GP says not to fasten in direct contact with masonry. Anybody know why?
Should I just use 1x PT for the drip cap shelf ? Is there a “best way” to fasten this 1x to the 4″ concrete edge?
Thanks in advance,
Eric S.
Replies
two things... 1st, GP Primetrim does best if it has solid backing.. if you fasten it to concrete it will follow the line of the concrete.. fasten some PT backer to the concrete and then your GPPT to the PT..
2d, you should have a capillary break between the concrete and the GP.. like grace, or another ice&water membrane
here's a sample of GPPT installed as a water table. over a pressure treated backer
Mike Smith Rhode Island : Design / Build / Repair / Restore
Several reasons, fastening is one of them. primetrim will ckeck, split or chip easily near edges. Whatever you use, PL Premium constuction adhesive is a good choice to hold it.
The primtrim will eventually rot in direct water contact. I have never seen it swell and while the internal adhesives (resins?) that hold the powder together are water-resistant, the wood particles themselves will eventually rot or support the growth of mold. Therefore, the code standard for not placing wood in direct contact with concrete still applies. There may be situations where it is the best choice of wood to use but when you ignore a manufacturters recommendations, you are out on your own limb.
Why not use FC for this situation?
Excellence is its own reward!
Thanks Mr. Piffin and Mike Smith (I searched for your photos of that FC job on the cape with the pumpkins but photos were not available).
I will seriously ponder the FC for the water table and support but in the meantime ...
Ok, so I fasten 1x PT to the 4" concrete edge and use some of the PL adhesive as insurance.
Nail 1x GPPT over the PT to act as the water table shelf. Put some membrane material over this and up the wall about 6".
Fasten some PT lath strip to the underside of another 1x GPPT to give it the drip angle.
Nail this combo piece to the shelf boards and membrane with flush SS nails.
Thanks for your help.
Eric S.
yes , that should work... prime all your backs and raw edges.. and caulk your joints as you assembleMike Smith Rhode Island : Design / Build / Repair / Restore
Credits, please! Who's that doing the hand modeling in the post with the pics?
the one with the clip on ponytail ? that's barry.. 'nam... 65-67Mike Smith Rhode Island : Design / Build / Repair / Restore