# wood blocking attachment



## djd76

I am getting ready to do a reroof(EPDM) for a GC. He has asked me to quote on attaching 2"x8" pressure treated lumber to the top of the CMU parapet wall. The drawings call for the cells to be grouted and anchor bolts set and the blocking attached to the anchor bolts ,but the owner wants to save money so the GC asked me if I can use a tapcon to attach the blocking.(no grouting or anchor bolts), I am thinking about trying to use lead expansion anchors along with construction adhesive like titebond or liquid nails. We will be installing metal coping on this wall later. Has anyone tried something similiar, and do you think it will work. On most previous jobs I have been on the carpenters have done this prior to our work, and it is usually anchor bolts.


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## Pie in the Sky

HA, we were just taling about something similar. It is possible to use tapcons, I have seen it done.16" oc Staggered with 2 on each end. Might have to trim the wood to get it to fit right. I def *would not* use expansion anchors on the thin walls of CMU. Like I said before Drill bit Size on Tapcons has no room for error. 

I personally would not do it. It should be grouted Then fastened. Anchor bolts arent a bad Idea but are never installed properly. Good luck, it will be pretty time consuming. Also be careful this wont ome back on you. If there are plans that show anchor Bolts they may be looking for it. I know thats a detail used by "Factory Mutual" If they dont catch that it wasnt installed correctly during construction and it fails, lookout!!!


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## Grumpy

Tapcons are fine, that's typically what we will use for our nailer atop parapet walls.

I agree CYA, make them sign a change order. In the change order state "change to specification per customer request. Use tapcons in lieu of lag bolts for a price reduction of.... "


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## 1985gt

Tapcons, unless this is a big project high wind, extended warranty, ect. Make sure to get it in writing. 

I agree this is rather odd on a project that has a GC, generally they are the ones who do this or have someone do it. Now that I think about it I'm not sure that is such a good thing.


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## djd76

It is a good size project for us, about 390sq with about 1500 LF of parapet wall, and a 15 year manufacturers warranty on the EPDM system only. Much of the existing CMU course is going to be replaced so we we will be attaching mostly to new blocks. I am going to try a test piece on the existing CMU and see how it works out. Thanks for the advice guys, confirmed a lot of what I was thinking.


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