I had a client request an estimate for a freestanding wooden pergola system in his backyard(New Jersey shore). There is an existing brick paver patio approx. 26′ deep X 46′ long. The pavers are installed atop a concrete slab.
pergola dimensions approx. – 25′ long X 10′ deep X 8′ height
posts 10″ X 10″ wrapped with 1X, bottom 1/3 brick masonry
beams either 2″ X 10″ 0r 2″ X 12″
rafters 2″ X 8″ or 2″ X 10″
wood species: either cypress or red cedar.
– 1) Is it suggested to fasten wood posts via metal post anchors tied into concrete slab, and then fastened into posts? or is it necessary to install footing for each post.
– 2) does anybody know if it is code to fasten pergola rafters to the beams with hurricane ties. For aesthetic sake, I plan to notch them into the beams, but if it is a requirement, I will use required fasteners.
-3) I am throwing around the idea of adding some masonry brick to the pergola project. I would like to add some veneer brick to box in the bottom 1/3 of each post, and also tied int to the outside faces of the upper 2″ X 12″ beams. I would border the brick with 5/4″ wood. Any suggestions for the highest quality/most durable exterior backer I could use that is rigid & would prevent joint cracks of brick? Any tips on the best veneer brick for exterior location? House is located right on the water(high moisture content).
Thank You! Chipper
Replies
Your questions at least partly center around what is considered a "structure" from the standpoint of the local code. In many parts of the country a pergola (of normal size) would not be considered to be a structure that is subject to the code and hence would not be required to have footings, ties, etc.
Of course, regardless of code you have an obligation to build something that is reasonably robust in standing up to storms and is not likely to create a hazard to humans or buildings due to flying debris.
On the brick idea, why not build completely out of brick and block... no need to just veneer over wood or similar substrate. I would think that a core of hollow 12x12 hadite block would be great and offer a recpticle that is a solid base for posts.
The difference between stupidity and genius is that genius has its limits. -Albert Einstein
http://www.peteforgovernor.com
i may use standard brick for lower 1/3rd section of post base. But i would like to tie in the face brick to the outer side of the 2 X 12 wood beams atop the posts. I chose not to build the entire column out of block/brick b/c it would be a mass of masonry - brick paver patio, stucco siding, brick columns....
theoretically, i thought wood-would add a nice touch of contrast aesthetically
With the pegola top being open, i dont think uplift is a concern, but do you think that fastening the posts to the slab would be adequate for lateral forces in stormy conditions?
even if the base and post are the same dimensions, you could still use the hoolow base center for a continuous post that will strengthen the entire column.
The difference between stupidity and genius is that genius has its limits. -Albert Einstein
http://www.peteforgovernor.com
the masonry will be hollow in the center, to accept wood post.
normally u would pour footings for the posts, but in your case, as long as the slab appears to be in good shape, i would think anchoring to the slab should be fine...I'd think frost is a concern there, and if the slab has held up for however long its been there, it should be alright...
being a pergola, i like the lower third of the posts being brick veneer, but i would stop there...personally, i think having brick up top would be too much...that's just me, plus i can't really stand bricks, especially the plain ol red colored ones..
I personally like the hue & character of salmon colored brick that is not perfectly square with imperfections(rounded edges, chips, divots...)
You left out one important issue with pergolas, they are top heavy and the typical right angle joinery doesn't hold the top structure rigidly. I don't think anchoring to the slab should be a problem, other than finding or making the post bases. Seismic forces may not be an issue in NJ and your frost would have already lifted the slab. The one thing I would advise is designing some angle bracing into the structure. Some I have built could be wracked easily, despite one being attached to the house. The grid like top framing has little lateral strength. Strong winds could knock one over.
Beat it to fit / Paint it to match
i just assumed he would have angle brackets...they are not even really an option, u have to have them...plus nicely made ones add character to the project..
Chipper (in my humble opinion)
The weight of a pergola as you describe should not need a footing if the existing slab is sound. Also if the frost has not been a problem to date, the wooden structure of the pergola should be flexable enough to accomodate any movement. As to the columns being 1/3 brick, you might want to think about that a while. Also, masony is not very flexable and is likely to crack if you have much movement. Look at some pictures of pergolas. You don't want the columns to get to massive. One thing that you did not mention is racking. Unless it is tied to an existing structure this could be a problem if the wind gets up a little. Corner brackets/bracing does not look to good. I have, in the past. anchored the columns with a continous threaded rod anchored in the slab up thru the column, through the beam with a nut and washer on top. About joist anchors. Don't use them unless you are in a high wind area. Want look good. Suggest that you use 4x12 beams with 2x8 rafters. Sorry did't mean to get so long winded.
We are currently building a pergola for a pool house project. The columns are cast which allows us to use threaded rods. The patio in the area is concrete pavers but we are putting in 12" diameter concrete footing with 1/2" anchor bolts. The threaded rods will extend through the column and will be countersunk in the beams. I plan on just putting a wood bung in the countersunk holes and sealing it well so water won't collect there. If it helps we are also in New Jersey - Moorestown - not at the shore, but building it for high winds regardless. I really don't think the deep footings are an option in New Jersey - we work at the shore too. I've never been able to get away with putting anything on a slab in this state, not that I would try anyway.
thank you for yor insight!