1/4" clearance on vinyl when its hot out?

[GiantScale]

I was wondering if I could make my clearance a bit smaller since the temp is already in the 90's and expantion should be close to maximum when installed.

1/4" isnt big for 12 foot pcs. But I have 25 foot long pieces and they are callinging for 3/4" clearance.

Thanks

[CThomp]

Call the manufacturer. They'd be able to give you the best advice on that.

[Big Builder]

Nothing worse than under spacing vinyl. But your point about installing it hot is a valid one.

[GiantScale]

I called royal yesterday and got the major runaround. "We will return your call" 4 hours later no call, I called again. Talked to a engineer who had no clue at all. He tried to belittle me by saying "you wouldnt understand the physics" I freaked, and said "I paid 4 grand for your siding and wont settle for that answer." He 'did' return my call later when I was gone and I will call again today.

From what I have read.. Subtract 1/4" when 90 degrees or over. Subtract 1/2" when 30 degrees or colder. And 3/8" when temps are in between.

http://www.taunton.com/finehomebuilding/pages/h00110.asp

This shouldnt be so hard to get this info. I guess I should have asked during the winter months when I had spare time.

[GiantScale]

The Royal engineer called back. He didnt know the expansion for a given temp change. But did recommend leaving a 1/2" "per side" on my 25' clapboard siding nailing the center tight.

The "Per side" was new to me.. Iv read everywhere "leave 1/4" clearance" (never did I read "both sides") and thought it ment total subtraction of 1/4" ,meaning 1/8" per side on a 12' 6" piece.
So I was going to double that with my 25' piece meaning 1/2" subtraction = 1/4" per side. The engineer says Im wrong. And all the expantion allowances Iv read ment "Per side"

So after I talked to him I called my supply house and was told the 1/4" I read everywhere means total subtraction or 1/8" "per side". What the heck??

Whos right? As soon as I told my supplier the engineer said "per side" he quickly changed his answer..

Someone here must know.. Is it a total allowance? Or "Per side"

[David]

Whos right? As soon as I told my supplier the engineer said "per side" he quickly changed his answer..

Sounds like you can disregard your supplier's advice. Perhaps you could check with other suppliers?

[GiantScale]

I think the royal engineer thought I was a "insider" checking how well his department was dealing with P.R. lol He had done allot of research and was very polite.

Yes. I continued to call around to other suppliers because my salesmen was NOT a installer. I talked to two other salesmen who had been installers before. First one said "a 25' piece of siding will not expand any more than a 12' 6" piece." I didnt agree on that. But its hard to stand ground when youve never done it and your talking to people who have for years. He said "allow 1/4" on both sides and that if I allowed 1/2" per side like the engineer said, it would "fall out" of the J channel receiver in the winter."

The second salesman I called I trusted the most. He had time ,and we talked for a while. He also said 1/4" "per side" but after telling him my story said "at least 1/4".

Which makes sense to me. If you go to the link I posted it says allow 1/2" when 30 degrees or under and 1/4" when 90 degrees or over. So the difference is 60 degrees and 1/4" allowance change. So if Im working in the 70's - 80's I would not expect the temp to rise more than 60 degrees (130 degrees in the sun) so 1/4" should be safe.

This looks like a large gray area to me. Or maybe Im over engineering it. But I will go with the small allowance of 1/4" perside. And if it buckle's, I will have to remove and redo which will be easier since Im useing S.S. #8 panhead screws.

Hey! I see you like the Hawkeys David. But your from Texas..?

[David]

Hey! I see you like the Hawkeys David. But your from Texas..?

I'm from Iowa. I live in Texas. :cool: I do like the Hawkeyes, even though I'm from Ames *gasp*.

Maybe you should go with 3/8". :)

[GiantScale]

Thanks Everyone. I hope Im making the right decision.

Its cooled down a little lately so yes. 5/16 to 3/8" allowance both sides of a 25 foot panel.

[GiantScale]

Just a follow up.
I did a test and measured a 25' piece when cool in the garage 73 degrees. Then drug it out onto a hot sunny drive way. Temp "said" over 120 degrees in the sun and I watched it grow before my eyes 5/16"