# Please Help! Sagging patio roof..



## Trav4011 (Apr 30, 2011)

Last year, I purchased a home that has a covered patio.. The cover consists of a lean-to, and it's sagging about 1" or so over a 12 1/2 ft span. 

The roof pitch is right at 1/12.. so, it's pretty flat.

The span is 12.5ft, from where it attaches to the house, to the header. The span is composed of 2x6 pressure treated pine (not sure what grade), on 16" centers. 

The cover is 15ft wide, with (3) 4x6 posts supporting the load. They are 7.5ft apart, and have double 2x6's nailed/glued together as the header. There is no evidence of sagging with the header.

The roof is 15x32's plywood, with a layer of tar paper, and shingles on top of that. 

Everything that I've read, says that 2x6 pine should be fine for this on 16" centers with a span of 12ft. Why is this thing sagging so much? It's only 2 years old. 

More importantly.. what can I do to fix the problem? I'd like to close the patio in, and put a ceiling in place, so going with 2x8's or bigger is out of the question. There simply isn't enough room overhead. Can I jack up the roof with bottle jacks, and nail/glue another 2x6 onto each existing one? Will this be enough support? Should I use a different type of wood?

Any help would be appreciated.. I don't know a great deal about the math involved.. but, I am capable of using a saw, hammer, and a nail gun. 

Travis


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## Trav4011 (Apr 30, 2011)

Here's a simple pic to show what I'm talking about..


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## tcleve4911 (Nov 6, 2010)

What part of the country do you live in?
Snow?

Is the sagging point just in the middle where the circle is, so the two rakes are okay?

If so, you may be able to jack that area up and sister on a couple more rafters.


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## mem (Dec 15, 2010)

I agree with cleve. I would also put on an appropriate roof covering for that 1 in 12 pitch. Shingles are not designed to work on a nearly flat roof. I wouldn't be surprised if you find out that wood up there is waterlogged, adding a considerable amount of weight, compounding the sagging issue.


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## Trav4011 (Apr 30, 2011)

Sorry.. Forgot about the location.. I'm in South Louisiana, so snow isn't a factor.

I considered the same for the singles, but the wood is bone dry. It looks like they used some sort of sealant as they laid the shingles down (not just the sealant strip on the single itself). Also, it hasn't rained here in over a month, so things are nice and crispy. 

The roof sags all the way across.. The rake is the portion that hangs over past the header, right? If so, that is fine. It's only 12" or so.

I thought about using (3) 2x6's in the center, glued/screwed together, where it rests directly on the middle 4x6 post. Then, double up the others. Would this be adequate? What type of lumber should I use?

Travis


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## Trav4011 (Apr 30, 2011)

Guess I'm going to try double 2x6's, glued and screwed together, with a strip of plywood between them. I'll do that every other 2x6, and see how that works out.

Travis


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## mem (Dec 15, 2010)

Trav4011 said:


> ...the wood is bone dry. It looks like they used some sort of sealant as they laid the shingles down (not just the sealant strip on the single itself). Also, it hasn't rained here in over a month, so things are nice and crispy.


Check it after a good rain and see if it is still dry. If it sagged after getting wet, it won't go back after it dries. A continuous bead of sealant across the shingles prevents any moisture that may get underneath from escaping.



Trav4011 said:


> The roof sags all the way across.. The rake is the portion that hangs over past the header, right? If so, that is fine. It's only 12" or so.


The rakes run from the house to the header-the slanted part on the sides. What you describe is the eave--the lowest part of the roof. So the rakes are sagging too?



Trav4011 said:


> I thought about using (3) 2x6's in the center, glued/screwed together, where it rests directly on the middle 4x6 post. Then, double up the others. Would this be adequate? What type of lumber should I use?


One would think 2x6 rafters would be adequate across a 12.5 foot span supporting nothing but a roof. Shingling a 1/12 pitch, on the other hand, is a fool's errand. Sistering the rafters would certainly not hurt anything, check the new rafters for a crown and put the proud side up. If there is another reason it's sagging, that is not addressed, it will probably sag again in a few years. Just my opinion.

Post some pics of the rakes, eave, underside and top--perhaps someone here can see what's going on.


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## Trav4011 (Apr 30, 2011)

Thanks for the advice.. 

I'll put a pair of water hoses/sprinklers up there today, and hit it for an hour or so. I've checked it before though, after a good/heavy rain, and the plywood is bone dry. The underside isn't closed in, so it's easy to see/get to. 

If it IS getting moisture under the shingles, and I decide to remove them. What's the best/lightest thing I can put up there to cover the plywood, that doesn't look like crap? 

The rakes are sagging as well.. but, not quite as much, because the 2x6's are doubled up on the outer posts, so it's beefier there. They might be sagging 1/4" or so.. which should be acceptable, right?

Thanks again..

Travis


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## kwikfishron (Mar 11, 2010)

Trav4011 said:


> Why is this thing sagging so much? It's only 2 years old.


Maybe some bonehead crowned them upside down. Wouldn’t be the first time.

How about posting some pictures.


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## Trav4011 (Apr 30, 2011)

Yeah, but ALL of them? lol..

I'll take some pics tomorrow. I went to Home Depot today, and got some 2x6's, plywood, and Liquid Nails, so I can make a few beams.


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## Gary in WA (Mar 11, 2009)

Be sure to use hot-dipped galvanized or stainless steel fasteners. Check the lumber stamp on the side for the grade number, #3 only span 10'1" with 20# dead load, 11'8" w.10#D.L.; R802.5.1(1): http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_8_sec002_par023.htm

Gary


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## Trav4011 (Apr 30, 2011)

GBR in WA said:


> Be sure to use hot-dipped galvanized or stainless steel fasteners. Check the lumber stamp on the side for the grade number, #3 only span 10'1" with 20# dead load, 11'8" w.10#D.L.; R802.5.1(1): http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_8_sec002_par023.htm
> 
> Gary


Gary,

If I use double 2x6's, with a piece of ply between them, glued/screwed together, I should be good to go?


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## SteelToes (Oct 5, 2010)

15/32" 3 ply ..I'd say that's to thin for 1/12' slope ...especially because you would want to cover that up with a torch down ...right ? Shingles are out of the question ...gotta be min of 2/12 slope for the shingles.

It's sagging beacuse they used PT lumber ..they probably framed it when was wet...so it settled down ..It never goes up.


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## Trav4011 (Apr 30, 2011)

I hit it with sprinklers for 2 hours yesterday.. It's was bone dry. I even went as far as to spray a heavy stream of water in one spot (right at a plywood seam), from a foot away, for about a minute straight, and it didn't leak. Even if it DID leak past the shingles, how would it get past the tar paper? 

The wood is pressure treated, as I stated in my first post. It is number 2 choice PT pine. I'm not sure if it was wet when they framed it or not.

Tearing it apart isn't an option. I WILL make it go back straight, whether that requires the use of laminated beams, or steel I-beams. One way or another, it will straighten out.


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## sixeightten (Feb 10, 2009)

Maybe it was built with the sag. Run a string across near where it si attached to the house to see if the sag is present there as well.


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## kwikfishron (Mar 11, 2010)

sixeightten said:


> Maybe it was built with the sag. Run a string across near where it si attached to the house to see if the sag is present there as well.


Something is a miss here, where’s the pictures?


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## Trav4011 (Apr 30, 2011)

It was hard to get a pic that showed the string that I ran..










If you look at the 3rd rafter, down from the top, you can see the string. It sags about 1 inch in the center across the span.

Travis


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## COLDIRON (Mar 15, 2009)

kwikfishron said:


> Maybe some bonehead crowned them upside down. Wouldn’t be the first time.
> 
> How about posting some pictures.


" That's not nice".


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## kwikfishron (Mar 11, 2010)

COLDIRON said:


> " That's not nice".


It wasn’t meant to be and now seeing the picture of what looks to be the rafters toe nailed into the existing fascia it would surprise me even less.

Sistering another 2x6 would help. I’d build a jack wall under the low point to lift the roof. Sister the rafter and remove the wall one rafter at a time as you proceed.


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## COLDIRON (Mar 15, 2009)

kwikfishron said:


> It wasn’t meant to be and now seeing the picture of what looks to be the rafters toe nailed into the existing fascia it would surprise me even less.
> 
> Sistering another 2x6 would help. I’d build a jack wall under the low point to lift the roof. Sister the rafter and remove the wall one rafter at a time as you proceed.


"Everybody that does work is not a bonehead maybe a diy did it, I don't know how some people on here get away with being abrasive when other people make one little comment out of line and get banned or told their banned if they do it again, you sir need to be crowned". Remember DIY not Pro site.


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## Underdog (Sep 4, 2009)

All wood will sag somewhat. The question, though, is if the sag is acceptable. Without knowing the exact type of wood and grade, we can't say for certain if it is acceptable though

If patio cover was designed for a deflection of L/180, a one inch sag would be close to acceptable. If it was designed for L/360, a half inch sag would be acceptable.


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## SteelToes (Oct 5, 2010)

Trav4011 said:


> I hit it with sprinklers for 2 hours yesterday.. It's was bone dry. I even went as far as to spray a heavy stream of water in one spot (right at a plywood seam), from a foot away, for about a minute straight, and it didn't leak. Even if it DID leak past the shingles, how would it get past the tar paper?
> 
> The wood is pressure treated, as I stated in my first post. It is number 2 choice PT pine. I'm not sure if it was wet when they framed it or not.
> 
> Tearing it apart isn't an option. I WILL make it go back straight, whether that requires the use of laminated beams, or steel I-beams. One way or another, it will straighten out.



Well, if you're gonna jack it up do it gradually an about 1/4 per day.

Just like kwikfishron said sistering another 2x6 would help,I'd just add some blocking as well.
I don't see a need for any kinda of beam.


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## Trav4011 (Apr 30, 2011)

I don't really care if someone is a bit exceptional in thier wording. I didn't build this thing. lol.. I'm just looking for some help from some folks who hopefully know a little more than I do. 

The rafters are not toe-nailed into the existing fascia.. There is a 2x6 that is screwed to the existing fascia with what appears to be stainless screws (4 between every pair of rafters). The 2x6 rafters are attached to that by galvanized brackets, and also screwed into place. The brackets have a strap that goes over the top of 2x6 that's screwed to the fascia, and I'm assuming that it's screwed in place up there as well. The brackets look like this..










They are "ridge rafter connectors".. So, I assume that they are up to the task.

The rafters sit on top of the double 2x6 header at the other end. They are toe nailed on the sides, and are also secured on the inside using these brackets..










Strong-tie hurricane ties. Everything is screwed together.. 

Travis


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## Trav4011 (Apr 30, 2011)

SteelToes said:


> Well, if you're gonna jack it up do it gradually an about 1/4 per day.
> 
> Just like kwikfishron said sistering another 2x6 would help,I'd just add some blocking as well.
> I don't see a need for any kinda of beam.


Can you explain what you mean by blocking?


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## Trav4011 (Apr 30, 2011)

loftezy said:


> All wood will sag somewhat. The question, though, is if the sag is acceptable. Without knowing the exact type of wood and grade, we can't say for certain if it is acceptable though
> 
> If patio cover was designed for a deflection of L/180, a one inch sag would be close to acceptable. If it was designed for L/360, a half inch sag would be acceptable.


Good to know.. What's the difference between the two? Sorry, I'm clueless.. lol. I can operate a saw, and follow directions, though.. so, I'm pretty sure that I can fix this up.


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## sixeightten (Feb 10, 2009)

Looking at the pictures you posted earlier gives us a good idea of what is going on. Looks like a few of the rafters are showing some deflection. Like a previous poster said, some deflection is acceptable. I would say that yours is just barely beyond that. I would find a few 2x6 with a slight crown, and sister these to every other one near the center. Or use a string and pick the worst offenders. Use a prop to bow the old rafters to match the new prior to nailing.


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## SteelToes (Oct 5, 2010)

Trav4011 said:


> Can you explain what you mean by blocking?


Blocking.


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## Trav4011 (Apr 30, 2011)

Ah.. I see.. I figured it had something to do with that. 

BTW, how does that strengthen the roof (in the way that I'm looking to beef it up)? Just curious..

Travis


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## SteelToes (Oct 5, 2010)

Blocking unifies the structure so the rafters share loads.


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## sixeightten (Feb 10, 2009)

I don't think the blocking will help on its own. I do think if you do the doubles and the blocking, it will help alleviate future deflection.


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## SteelToes (Oct 5, 2010)

sixeightten said:


> I don't think the blocking will help on its own. I do think if you do the doubles and the blocking, it will help alleviate future deflection.


_Just like kwikfishron said sistering another 2x6 would help,I'd just add some blocking as well.
_
Agree.Already proposed.


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## sixeightten (Feb 10, 2009)

I would put the blocking in the center of the span. The pic shows it at the end.


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## Trav4011 (Apr 30, 2011)

SteelToes said:


> Blocking unifies the structure so the rafters share loads.


Gotcha.. I will double up every other 2x6 using glue/screws, and add blocking in to tie it all together. 

I'll post some pics when I'm finished.

Travis


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## Gary in WA (Mar 11, 2009)

The p.t. wood rafters were probably at high moisture content at install. Maybe the lowest one is crowned down instead of up. The installer stood/knelt on the roof deck in-line with the rafter as he nailed the plywood off with a hammer. His weight (100-200#) leveled the wet (weakened) rafter out (or more, if crowned down) locking the plywood in that elevation acting as a “tee”; Fig. 8-11 and pp. 144; http://books.google.com/books?id=1uYilfqCppIC&pg=PA138&lpg=PA138&dq=sistering+joist+with+plywood&source=bl&ots=lJw79uvfPl&sig=i98E9_bym7MvE9VsjxE7AL7MQk0&hl=en&ei=3xnBStq7JIyIsgPtp5Ao&sa=X&oi=book_result&ct=result&resnum=7#v=onepage&q=sistering%20joist%20with%20plywood&f=false
You can do the same thing sheathing a standing wall that hasn’t been plumb/line for straight first. It’s very hard to move depending on the gravity of the curves (it holds the shape after nailing sheathing on). Then it dried out in that locked position. 

I doubt solid blocking will help because the slop in the joints will give-up most of what you will gain with a jack stick. Bridging would work because it is in-line with the diagonal support you need for the non-sistered ones. (Acting as a strut on a diagonal).http://books.google.com/books?id=DW...page&q=bridging to strengthen a floor&f=false


The rafters, without a snow load, are far under-spanned for the loads. Go here; http://www.awc.org/calculators/span...d=10&submit=Calculate+Maximum+Horizontal+Span

Enter: SP---2x6---#2---L-360---Rafter with snow---16”---No (wet conditions)---No (incised)--- *0.01* (snow load) ---*7* (dead load)---(calculate)

Fasten a string line under the rafter’s middle section with a 1-1/2” spacer at each end. Check the worst (lowest) one, decide to jack it with a spring stud under it or hydraulic (harder) jack. If it moves minimally (I’m guessing), then cut partway through it at the middle, then spring it up. This will relieve the plywood “tee” resisting and the crown set. Do this to the lowest ones, not every other one as there is no live load or snow, ever. Sister it while in the raised position according to the string elevation. Why sister ones that don’t need it????? Waste of time and money, I seriously doubt they will sag anymore after initially drying at install, without any load above. 



Gary


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## tcleve4911 (Nov 6, 2010)

When you go to the lumber yard, take some time to pick through the pile and find the ones that have a noticeable crown in them.
Put the crown up when you sister to your (crown down) rafters.
This will help straighten the sag.

Blocking doesn't do much in this case but if you want to, go ahead.
I'd run two staggered courses dividing the roof into thirds.
You'll only be able to toenail the blocking since each rafter's going to be 5 1/2" thick now.

That's l1-1/2"l(sistered rafter) + l1/2"l(plywood and glue)+l1-1/2"l (existing rafter) +l1/2"l +l1-1/2"l

That oughta do something.....:yes:


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## Trav4011 (Apr 30, 2011)

Thanks for all of the advice! I'm going to take a stab at it this weekend. I'll post my results!


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