Hi all,
I’m installing a Trademark (Azek) railing on concrete footings.
I’m going to use this suface mount bracket (SMB) that they sell to attach the post to the concrete. The SMB is a short, hollow 16″ post of galvanized metal with a flange to attach to the concrete. They recommend sliding a trimmed down PT 4×4 into the SMB to make up the difference between the 16″ and the final post height. Then the whole assembly gets covered.
So it’s PT fitted right inside a galvanized steel sleeve. Full contact.
I’m concerned about corrosion. How is this handled? Any suggestions? Azek said “they’ve never heard of corrosion for this.”
Replies
you should be using the Tall Boy SMB, they do not need a 4x4 post...check the link
Where are you getting the rail sysytem from? Harvey Building Products?
You do realize that the Azek railing is not a vinyl railing but a wood polymer with a PVC coating?.....
http://www.azek.com/setcontrol/download_file.php?id=16&table=product&field=reference_document_8_file
Geoff
Hi GeoffOne of the methods Azek has for installing the post is to use a short SMB (16") and then slide a PT 4x4 into the SMB. The Trademark post (sleeve) then slides over this. The SMB is about $55/each here.The alternative is to go with the highboy and no PT. That's over $100.I was looking doing the first to avoid the extra expense.I do understand that Azek is not vinyl. I don't see how that's relevant though - maybe I'm misunderstanding your point?
My point was as stated by Piffin, thanks Piffin!,
as for the PT vs. the SMB I believe they are a coated material, not bare metal, so should pose a minimal concern for corrosion. 30# felt or Vycor will work too, to protect the metal, as for fit when doing so, it should pose no problem, as you are fastening the 4x4's to the SMB's with screws and setting them plumb as you go.
One thing I have heard of is the PT posts twisting as they dry and splitting the sleeves, hence the invention of the Tall Boys.
Geoff
Gotcha. Thanks.I'm wondering how important it is for that mini post midspan to be on solid footing. I know it can't just sit on the dirt, but to just set a block in the ground for that - not a real footing.Turns out the cost diff for the tall boy is not as much as the lumberyard guy originally guessed - only about $85 vs $55 for the smb. Wife is willing to spring for the extra $ so I can have a bit easier installI took a look at the azek version of the smb and it doesn't look coated. The brochures showed what I guess was a previous verision that had a coating.thanks for your input.
I've used this system when it was ?Weatherbest? before Azek bought that company out. Since Azek has only had it a short time, they might be honest in saying they have not heard about problems.
But I have not had problems fitting your concerns myself.
In genreal, the problem happens mostly in the presence of water and not wshere the PT is kept dry, so the corrosion might be minimal.
OTOH, it could just be that the problem is slow and since it is hidden by the sleeve, it is a disaster in waiting. To avoid it, you can use a barrier like 30# tarpaper of vyvor between post and the mount.
One problem I did have was that since PT tends to be swollen oversized, I had to shave some of the posts to fit.
Save your scrap cutoffs from those sleeves. They are handy for several things. I have done some sign post and mailbox installs where it is desirable to remove them in the winter - seasonal homes. I use them for a sort of interior sleeve form for concrete in the ground. That way the 4x4 post can slip into t he ground and pull right back out again for winter, putting a scrap 4x4 in the hole so they can find it again in spring. I pour it so there is gravel at bottom for water to drain away.
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Thanks Piffin!I thought about the Vycore. Wasn't sure if that would add too much slop to the post - SMB fit. But I can give it a try.Since you've done a few of these, any other tips on installing these?We are putting it along the top of a block retaining wall - just 4 posts and 3 rail sections. I'm having the retaining wall guys pour separate footings for the posts - rather than use the top of the retaining wall itself. I figure 8" square footings about 2 feet deep. The BI didn't seem to care.Anyway, any other tips you've got would be appreciated.
I think thepoint was made that this is not vinyl because some assume that with Azek being a cellular polyVINYLchloride, that anything with the Azek name on it must be a PVC product also.It is relevant because those products sag lineally under their own weight and are not good for railings.With this poroduct, the strength is in the underlying composite, and the savings in paint is in the PVC coating.You will want some patience, because IMO, the SS screws they send in the kits are too soft and we break quite a few. I keep a supply of GRK on hand anyways so no sweat for me.This is both the 1-1/4" for ballusters to rail and the larger for fixing to post at the metal support angles. For those I like the GRK laghead structrual screws, then touch them up white
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As fpr that type of install on top of a block retaining... I'm thinking....I believe I would just use allthread set in a poured block core and mount the haredware sleave to it with a nut. That'd save you enough for a night out with the Missus
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Thanks for the advice Piffin. I'll look at the top of the retaining wall again. And I'll get some extra SS screws. Been meaning to pick up some grks. Last set of SS square drives I had were garbage.
If possible how about black locust for the posts. I use it for fence posts ,swing set etc. I realize not all parts of the country have access to black locust. Three years ago I paid $1.90 for log run 8'-0" 4x4's. Log run means you get what comes thru sawed. I always order 25% more than I need. None is dried , you pay extra for kiln drying. I think,not sure though I paid $1.00 per post for the kiln.Less than $3.00 per post and might last as long as PT.
I would think depending on where you live that several species would work for posts,cedar,cypress ,white oak,redwood out west,Ipe ,etc.
mike
Good point. The way they are contained in the sleeve, they will never be getting wetter than the day the caps go on
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