Expert: Dan Griffin - 4/16/2008

Question
I am building a small triangular corner deck that needs support along the walls, the long leg of the triangle is on footings. Weight is very minimal. I was going to excavate an existing set of masonry stairs and dig new pier for support since my 2 intersecting walls are hollow cmu's. Then I was told from an structural engineer that I can use the Hilti system. I was anxious to save the labor and try the system so I tried to contact the tech support on the website. No luck. Then Im at Home Depot and they have a Hilti rep so I talk to him and he tells me the same thing the fasteners with the epoxy and screen insert. 525lbs per bolt tension strength and 790shear. Great I tell myself I'll over kill this 16 o/c on both walls. The whole load is 2000 at best. This crap didnt work at all, I can pull the fastener rods out by hand after 5 hours of curing. Now what? Too be honest its 9x7 and projects out 8ft so the fasteners can certainly handle the shear Im just not sure about the lateral support. I was thinking I could gusset my front support posts and between the gusset and the corner design I may not have any out pull. I hope I didnt lose anyone. I dont know if I didnt pump enough epoxy into the sleeves or these people didnt advise me too well. Any other ideas?
http://www.us.hilti.com/data/techlib/docs/product%20technical%20guide%202001/anc...(176-185)r009.pdf


Answer
Hilti certainly makes some excellent products. I use ITW Redhead C6
http://www.itwredhead.com/
, a 2 part that requires a special gun and mixing tips, because of my local supplier.

Epoxy anchors need the proper quantity.  I suspect it may have been cold when you did this, it is hard to pump the epoxy and set times can be much longer.  I like to fill the screen/sleeve/mushroom, push the allthread in, pull it back out to see if has plenty of goop on it, add more if required (usually to the bolt itself), and re-install.  The particular type I use provides an initial set in 15 minutes, enough to snug up bolts but not enough to truly tighten until the next day.  Something is very wrong if you can pull them out bare handed.  Epoxy does have shelf life.  Were I you, I would contact Hilti customer service:
http://www.hilti.com/holcom/modules/contacts/cnts_listpage.jsp?cntrycode=US
for input.  I am sorry that your first adventure into epoxy anchors has problems.  I have had some few problems, but many more successes.