[skitch4110]

Hello,
I built this porch covering after getting the run around from local builders who either felt the job was too small or they just didn't return my call. Anyway I am a little concerned with structural integrity. It is my first DYI project on structure. The cover is only attached by 2x6 joist for support only. The roof is 1/4 decking with 4x8 sheets of corregated roofing material that weigh 18 pounds per sheet. Overall there is very little weight on the structure. I explained the plans to the builder at Southerlands and he thought this would be plenty of support. I am really not wanting to put beams midway underneath, but may have too. The span between 4x6 post is 14'. Any suggestions? Ok, you pros can stop laughing!:laughing:

 

[Scuba_Dave]

Where are you located? Snow load?

1/4" decking? I've seen 1/2" as the bare min
Is it sloped so rain will run off?

 

[skitch4110]

I'm located in Oklahoma and actually the decking is 7/16 not 1/4. We have had planty of rain to test out the slope and it works very good! Snow load should be ok but not sure how to measure that.

 

[Scuba_Dave]

Well according to one span calc I use a 2x6 rafter with snow load will only span around 12' when installed 16" OC (on center). This depends upon species of wood & the grade - #2 grade being the normal every day wood you find - HD & Lowes

Span calc:

http://www.awc.org/calculators/span/calc/timbercalcstyle.asp

You have a 4x6 in the middle of the ceiling as a beam
Are the outer beams also 4x6?
And the overall length is 28' ? - 14' between posts ?
There are more posts along the brick wall...or is that a gutter ?

 

[skitch4110]

All beams are 4x6, there are 4 total beams from house to outside edge. (shown best in second picture) Thanks for the snow load calculator, I may have to modify this setup which can be done I just hate to change this far into it, but it's my fault for not using 6x6 beams $$$. The joist lengths are 8' and 6'. The span of the beams between post ( pic#2) is 14'.

 

[Scuba_Dave]

Nope, hold on -- you might be OK
I was talking joist span - which if you only have 8' & 6' you are fine
The beam span is 14' 4x6 - I'll have to see if I can find a span calc for that
Unless someone else has a link

 

[Wildie]

In my area, great concern is taken by the building department about wind lift.
Have you taken into consideration this possibility?

 

[ARI001]

All I could find was spans based on total load per lineal foot 4" x 6" beams, but here you go anyway:
8' span w/ total load of 223#
10' span w/ total load of 142#
12' span w/ total load of 95#

 

[AndrewF]

In my area, great concern is taken by the building department about wind lift.
Have you taken into consideration this possibility?

Same here. Are the 4x4 posts anchored to the slab?

 

[skitch4110]

Not yet but they will be this weekend. I was thinking I could use a metal plate cut 4x6 to keep water from wicking ( any more) up the post on the porch floor. I have some concrete glue but have not used it before. I wanted to keep the post anchored but without hardware on the sides of them. Has anyone used this method before?
Thanks!

 

[skitch4110]

Arioo1....Excellent! Thanks a bunch!

 

[Michael Thomas]

Are those posts just sitting on the slab, or did you pour footings?

-----------
[FONT=&quot]Home Inspection: "A business with illogically high liability, slim profit margins and limited economies of scale. An incredibly diverse, multi-disciplined consulting service, delivered under difficult in-field circumstances, before a hostile audience in an impossibly short time frame, requiring the production of an extraordinarily detailed technical report, almost instantly, without benefit of research facilities or resources." - Alan Carson[/FONT]

 

[skitch4110]

They are sitting on the slab.

 

[Wildie]

They are sitting on the slab.

May be advisable to use ABU44 or ABU66 post anchors! This is what was engineered for my roof!

http://store.qualitydist.net/sst-abu66.html

 

[Scuba_Dave]

Nope, hold on -- you might be OK
I was talking joist span - which if you only have 8' & 6' you are fine
The beam span is 14' 4x6 - I'll have to see if I can find a span calc for that
Unless someone else has a link

All I could find was spans based on total load per lineal foot 4" x 6" beams, but here you go anyway:
8' span w/ total load of 223#
10' span w/ total load of 142#
12' span w/ total load of 95#

The only calc I could find said that with joists & span & distance between beams you needed (2) 2x12's which = 3" x 9.25"
You have a 4x6 = 3.5" X 5.5"...so it seems the beams are undersized
But you need a deck person to confirm loads

You do need the posts connected to the cement pad
A good strong wind coming in is going to lift that whole thing right up
Might not happen for years...but it will happen
I do not think concrete glue will work - migh be wrong
The simpson strong tie is what you want - about $16 I think

 

[skitch4110]

I know what I'll be doing Saturday! thanks everyone for all of your input!

 

[DaVinci]

I agree with the info given by Scuba Dave and Wildie! But lets look at just one more item! How is the roof attached at the house? Is the roof just attached to the freeze board? What do the posts against the house do?

Paul

 

[Scuba_Dave]

I know what I'll be doing Saturday! thanks everyone for all of your input!

Ok, now I'm really getting myself twisted around
I just realized the sizing spec I used is for a deck you are walking on
And this is "only" a roof - less load ( I think)

So....sorry - but I can't find anything to verify the sizing of the beam as a roof

 

[Scuba_Dave]

I did find this in a search
The person had a 14' span with new (2) 2x6's that was sagging supporting a porch roof. The roof was 14' x 6'

http://newsgroups.derkeiler.com/Archive/Alt/alt.home.repair/2008-01/msg02624.html

The building inspector came out to do the framing inspection before it was
covered up by the new vinyl. The first thing he said is there is a sag in
the middle that he could see right away just driving down the street while
approaching the house. Then he said he thought it may be "under span" and
measured that the span is 14 feet. He said he would check whatever
reference chart he had and said that using 2 2x6's is insufficient for a
14-foot span.

 

[ARI001]

(2) 2x12's which = 3" x 9.25"

(2) 2x12= 3" x 11.25"