Arbor/ Trellis design questions

Dean W. · 04-30-2012, 11:15 PM

I'm building an arbor/ trellis and am wondering if anyone can give me suggestions how to build this thing. I have attached a basic sketch of the dimension of what I'm going for. On the right hand side I drove some t-poles into the ground. So far I tied some 2x4s with wire to two of them. My question is should I plant the 2x4s in the ground instead? These are pressure treated 2x4s. If so how deep would it be necessary to prevent the collapse of this thing? I was estimating 12" deep though I could go as deep as 18" and still have enough board left over to equal 6.5' on top. Only problem is digging that deep turns into more and more rocks. So if anyone is pretty handy please advise.

Thanks for looking!

sunfish · 05-01-2012, 07:35 AM

Quote:

Originally Posted by Dean W.

I'm building an arbor/ trellis and am wondering if anyone can give me suggestions how to build this thing. I have attached a basic sketch of the dimension of what I'm going for. On the right hand side I drove some t-poles into the ground. So far I tied some 2x4s with wire to two of them. My question is should I plant the 2x4s in the ground instead? These are pressure treated 2x4s. If so how deep would it be necessary to prevent the collapse of this thing? I was estimating 12" deep though I could go as deep as 18" and still have enough board left over to equal 6.5' on top. Only problem is digging that deep turns into more and more rocks. So if anyone is pretty handy please advise.

Thanks for looking!

Dean I don't think 2x4s will be rigid enough. 4x4s or even metal pipe would be better for the uprights.

Dean W. · 05-01-2012, 07:44 AM

Okay, do you think they might last a few years? I don't really need this to last a long time. I just wanted to build it cheaply.

sunfish · 05-01-2012, 07:54 AM

Quote:

Originally Posted by Dean W.

Okay, do you think they might last a few years? I don't really need this to last a long time. I just wanted to build it cheaply.

Treated wood should last at least a few years. I think only the four corner post need to be a little beefier. Even maybe just double up the 2x4s n the 4 corners.

Dean W. · 05-01-2012, 07:57 AM

Cool, I guess I'll dig the corner poles then. It will have cross members going across and all the way across on one side. So this should stabilize it somewhat.

Dean W. · 05-01-2012, 05:22 PM

This is what I built. Nothing to fancy. Decided to stay w/ the 2x4s they were cheaper. I hope the 1x2 atop the structure can support some weight. I'll add a few more.

GreenFin · 05-01-2012, 11:51 PM

Congrats! Looks like you're making good progress.

Did you dig holes and set the 2x4's into the ground a ways? Did it end up stable enough for you? Hopefully it did, but if not it would add a lot of rigidity to add "X" bracing on the sides. You can use small stuff like 1x2's for it if you wanted.

What I mean by X bracing is this: the long sides of your trellis have 4 vertical posts; if we number them in order 1 through 4 from one end to the other, then what I'm suggesting is nailing one end of a 1x2 to the top of post #1 and to the bottom of post #2, then adding another 1x2 nailed to the top of post #2 and the bottom of post #1, then repeating that process to put X bracing all around it. I think you'd end up with 6 X's: 2 on each long side, 1 on each short side. Or 8 if you put a couple over the roof as well.

That could well be overkill, I don't know, but you'll make it work. I'm looking forward to the pics of it once it's covered in flora

Dean W. · 05-02-2012, 12:23 AM

Hey GreenFin,

Yes, I put 6 of them in the ground about 13" deep. I think it's pretty stable and can handle the wind and what not. I just don't know about the weight from the vine and fruits that will be on top. Time will tell I guess. I didn't think of X bracing it. That's something for me to consider though it doesn't seem wobbly.

Thanks for the advice!

Scuba_Dave · 05-02-2012, 07:30 AM

What is going to be growing on the trellis ?
How long do you expect/want to use it ?
More important then the weight is the effect of wind on the structure once the vine etc grows out
Once the structure has vines on it then the wind force increases & in many cases will blow it over
If you only want to use it for 1 growing season then what you built may work
But a 40-50 mph wind may blow it over

If the 1x2's are reg wood then they will not last long, the grade of wood used to make them is not that great
Also a single nail in each end of the 1x2 shown in the pic will not prevent the structure from moving/swaying
The "X" bracing will greatly increase the strength of the structure
"Fresh" built most things seem stable, its once wind/water & sun start taking their toll that the wood/structure will start to move as time goes on

I use PT 4x4's for (almost) all uprights when I build something, or larger - for my deck
One exception being my greenhouse -but its attached to the house & bolted to a cement foundation

Dean W. · 05-02-2012, 08:47 AM

Hi Scuba_Dave,

I only expect it to last a few years. I plan on planting gourds on there. The 1x2s are treated wood. You and Tony are right about using 4x4s. I think I'll check the price on them and maybe reconsider. At least maybe 4 of them.

Thanks!

GreenFin · 05-02-2012, 11:19 AM

Quote:

Originally Posted by Dean W.

Hey GreenFin,

Yes, I put 6 of them in the ground about 13" deep.

Probably wise.

Quote:

Originally Posted by Dean W.

Hi Scuba_Dave,

I only expect it to last a few years. I plan on planting gourds on there. The 1x2s are treated wood. You and Tony are right about using 4x4s. I think I'll check the price on them and maybe reconsider. At least maybe 4 of them.

When I made the vertical supports for my greenhouse, I did like Tony suggested above and used pairs of 2x4's screwed together to form my own 4x4's because it was cheaper than buying 4x4's. So rather than buying four 4x4's you could just get four more 2x4's and augment your existing corners if you wanted.

Your trellis looks like it'll be pretty sheltered from the wind. Is that the case, or is it somewhat exposed?

Gourds will look nice on it.

Dean W. · 05-02-2012, 12:54 PM

Hey GreenFin,

Yes, I planted those bushes there years ago that act as a wind screen from the North and also provide some privacy.

I went ahead and bought 6-4x4s as per the suggestions I got here. I'll use the 2x4s as cross supports. Already got two holes dug 18-20" deep so I just need to dig 4 more. Then I'll need to line them up and level them a bit. It's a little difficult because it's on a slight hill. So I may use a string with a level.

Thanks for everyone's suggestions. I should have listened the first time, but sometimes we don't want to hear the truth I guess.

GreenFin · 05-02-2012, 01:55 PM

That thing might be hurricane-proof by the time you're done with it

Scuba_Dave · 05-02-2012, 05:49 PM

I actually have over a dozen "spare" PT 4x4's & a few 4x6's
I've taken down 2 pool decks that people were getting rid of & reclaimed the wood

On my greenhouse instead of attaching the 2x4's width to width to make a 4x4 I made an L shape at the corners with the 2x's

Dean W. · 05-02-2012, 05:53 PM

Quote:

Originally Posted by GreenFin

That thing might be hurricane-proof by the time you're done with it

It should be now and it's a lot of work I hope they're worth it.

Quote:

Originally Posted by Scuba_Dave

I actually have over a dozen "spare" PT 4x4's & a few 4x6's
I've taken down 2 pool decks that people were getting rid of & reclaimed the wood

On my greenhouse instead of attaching the 2x4's width to width to make a 4x4 I made an L shape at the corners with the 2x's

That's good that you got to reuse some wood. I put an add on freecycle didn't turn up anything, but some 1x4s which I might use across the top.

Dean W. · 05-03-2012, 02:27 PM

Finally got the 4x4s in the ground. It may get a little shade in the late afternoon, but I think I should be able to grow them here. Need to nail the 2x4s atop this thing and prepare the soil.

sunfish · 05-03-2012, 03:22 PM

Quote:

Originally Posted by Dean W.

Finally got the 4x4s in the ground. It may get a little shade in the late afternoon, but I think I should be able to grow them here. Need to nail the 2x4s atop this thing and prepare the soil.

Looks good.

Olafhenny · 05-05-2012, 11:42 PM

Sorry, Dean, I am a bit late, but it looks, like you need a bit of engineering advise. As your structure
stands now, I disagree with Scuba Dave that it will blow over at 40 to 50 mph winds. If you put
anything on it, which will catch the wind, such as vines, it will blow over at less than 20 mph. Your
joints at the corners will act like hinges and make the structure fold like a card house, digging the
posts deep will help a little, but not enough.

The very least you will need is diagonal cross strapping. No need to do it across the whole span of
the beams. 3 feet x 3feet from the cross beams to each post will give it plenty of stability.

But if you want that structure to stand up for 10 years or longer, I am afraid you will have to start from
scratch: Dig the post holes about 1 foot deep and at a diameter of about 8 to ten inches. Important
is, that the walls of the holes are undisturbed soil (no lose dirt). Fill the holes with ready mix
concrete. You will need a bag for each 2 to 3 holes. Into that concrete you plant a post bracket
for each post as you see in the top left corner of this site:

post base brackets - Google Search

Make sure these brackets are lined up, sighting from post to post. Having them all the same
elevation will help too. You can ensure that, by using a carpenter’s level and the straightest one
of your 2x4s for the top frame to get them all to the same height.

The idea of the brackets is, that you do not want to have direct contact between concrete and
wood, no matter how well the wood is treated, incised or otherwise. Concrete will make and
wood rot prematurely.

Another bit of advise: Don’t torture yourself by using nails. Beg, steal, borrow or rent a
cordless drill and use 3” special screws for treated lumber. The job will go twice as fast and will
require a lot less foul language to get it done.

Good luck,
Olaf

PS: I am adding a couple of pictures from my own gazebo construction eight years ago.

You can see, I kept the diagonal strapping a bit shy, but I could afford that, because of the diagonal grid of all the
minor straps.

This is an attempt to blow up part of the previous picture to show the post sitting in the bracket,
which in turn sits in the concrete. It is important, that the concrete is right against the base of the
bracket, for stability, but does not touch the wood.

sunfish · 05-06-2012, 12:05 AM

Use galvanized steel post 2' in ground and carriage bolts it will last 100 years

Olafhenny · 05-06-2012, 12:39 AM

Quote:

Originally Posted by sunfish

Use galvanized steel post 2' in ground and carriage bolts it will last 100 years

No it won't. Thin posts like that won't give enough purchase. They will 'cut' the dirt unless set in
concrete to provide a larger surface to withstand lateral force.

04-30-2012, 11:15 PM	#1 (permalink)
Dean W. Dean W.'s Photo Gallery Location: Cedar Park, TX Zone: 8b Join Date: Sep 2007 Posts: 4,279 BananaBucks : 234,340 Feedback: 13 / 100% Said "Thanks" 6,325 Times Was Thanked 2,130 Times in 972 Posts Said "Welcome to Bananas" 300 Times	Arbor/ Trellis design questions I'm building an arbor/ trellis and am wondering if anyone can give me suggestions how to build this thing. I have attached a basic sketch of the dimension of what I'm going for. On the right hand side I drove some t-poles into the ground. So far I tied some 2x4s with wire to two of them. My question is should I plant the 2x4s in the ground instead? These are pressure treated 2x4s. If so how deep would it be necessary to prevent the collapse of this thing? I was estimating 12" deep though I could go as deep as 18" and still have enough board left over to equal 6.5' on top. Only problem is digging that deep turns into more and more rocks. So if anyone is pretty handy please advise. Thanks for looking! __________________

05-01-2012, 07:44 AM	#3 (permalink)
Dean W. Dean W.'s Photo Gallery Location: Cedar Park, TX Zone: 8b Join Date: Sep 2007 Posts: 4,279 BananaBucks : 234,340 Feedback: 13 / 100% Said "Thanks" 6,325 Times Was Thanked 2,130 Times in 972 Posts Said "Welcome to Bananas" 300 Times	Re: Arbor/ Trellis design questions Okay, do you think they might last a few years? I don't really need this to last a long time. I just wanted to build it cheaply. __________________

05-01-2012, 07:57 AM	#5 (permalink)
Dean W. Dean W.'s Photo Gallery Location: Cedar Park, TX Zone: 8b Join Date: Sep 2007 Posts: 4,279 BananaBucks : 234,340 Feedback: 13 / 100% Said "Thanks" 6,325 Times Was Thanked 2,130 Times in 972 Posts Said "Welcome to Bananas" 300 Times	Re: Arbor/ Trellis design questions Cool, I guess I'll dig the corner poles then. It will have cross members going across and all the way across on one side. So this should stabilize it somewhat. __________________

05-01-2012, 05:22 PM	#6 (permalink)
Dean W. Dean W.'s Photo Gallery Location: Cedar Park, TX Zone: 8b Join Date: Sep 2007 Posts: 4,279 BananaBucks : 234,340 Feedback: 13 / 100% Said "Thanks" 6,325 Times Was Thanked 2,130 Times in 972 Posts Said "Welcome to Bananas" 300 Times	Re: Arbor/ Trellis design questions This is what I built. Nothing to fancy. Decided to stay w/ the 2x4s they were cheaper. I hope the 1x2 atop the structure can support some weight. I'll add a few more. __________________

05-01-2012, 11:51 PM	#7 (permalink)
GreenFin Location: Kansas Zone: 6a Join Date: Jan 2012 Posts: 595 BananaBucks : 87,575 Feedback: 0 / 0% Said "Thanks" 1,396 Times Was Thanked 939 Times in 334 Posts Said "Welcome to Bananas" 44 Times	Re: Arbor/ Trellis design questions Congrats! Looks like you're making good progress. Did you dig holes and set the 2x4's into the ground a ways? Did it end up stable enough for you? Hopefully it did, but if not it would add a lot of rigidity to add "X" bracing on the sides. You can use small stuff like 1x2's for it if you wanted. What I mean by X bracing is this: the long sides of your trellis have 4 vertical posts; if we number them in order 1 through 4 from one end to the other, then what I'm suggesting is nailing one end of a 1x2 to the top of post #1 and to the bottom of post #2, then adding another 1x2 nailed to the top of post #2 and the bottom of post #1, then repeating that process to put X bracing all around it. I think you'd end up with 6 X's: 2 on each long side, 1 on each short side. Or 8 if you put a couple over the roof as well. That could well be overkill, I don't know, but you'll make it work. I'm looking forward to the pics of it once it's covered in flora __________________ Set out runnin', but I'll take my time; a friend of bananas is a friend of mine. www.GreenFinGardens.com

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05-02-2012, 12:23 AM	#8 (permalink)
Dean W. Dean W.'s Photo Gallery Location: Cedar Park, TX Zone: 8b Join Date: Sep 2007 Posts: 4,279 BananaBucks : 234,340 Feedback: 13 / 100% Said "Thanks" 6,325 Times Was Thanked 2,130 Times in 972 Posts Said "Welcome to Bananas" 300 Times	Re: Arbor/ Trellis design questions Hey GreenFin, Yes, I put 6 of them in the ground about 13" deep. I think it's pretty stable and can handle the wind and what not. I just don't know about the weight from the vine and fruits that will be on top. Time will tell I guess. I didn't think of X bracing it. That's something for me to consider though it doesn't seem wobbly. Thanks for the advice! __________________ Last edited by Dean W. : 05-02-2012 at 12:24 AM. Reason: added

05-02-2012, 07:30 AM	#9 (permalink)
Scuba_Dave Location: South of Boston, MA Find me on the map! Zone: 6-7 Name: Dave Join Date: May 2009 Posts: 732 BananaBucks : 58,442 Feedback: 0 / 0% Said "Thanks" 501 Times Was Thanked 1,218 Times in 451 Posts Said "Welcome to Bananas" 2,414 Times	Re: Arbor/ Trellis design questions What is going to be growing on the trellis ? How long do you expect/want to use it ? More important then the weight is the effect of wind on the structure once the vine etc grows out Once the structure has vines on it then the wind force increases & in many cases will blow it over If you only want to use it for 1 growing season then what you built may work But a 40-50 mph wind may blow it over If the 1x2's are reg wood then they will not last long, the grade of wood used to make them is not that great Also a single nail in each end of the 1x2 shown in the pic will not prevent the structure from moving/swaying The "X" bracing will greatly increase the strength of the structure "Fresh" built most things seem stable, its once wind/water & sun start taking their toll that the wood/structure will start to move as time goes on I use PT 4x4's for (almost) all uprights when I build something, or larger - for my deck One exception being my greenhouse -but its attached to the house & bolted to a cement foundation __________________ .

05-02-2012, 08:47 AM	#10 (permalink)
Dean W. Dean W.'s Photo Gallery Location: Cedar Park, TX Zone: 8b Join Date: Sep 2007 Posts: 4,279 BananaBucks : 234,340 Feedback: 13 / 100% Said "Thanks" 6,325 Times Was Thanked 2,130 Times in 972 Posts Said "Welcome to Bananas" 300 Times	Re: Arbor/ Trellis design questions Hi Scuba_Dave, I only expect it to last a few years. I plan on planting gourds on there. The 1x2s are treated wood. You and Tony are right about using 4x4s. I think I'll check the price on them and maybe reconsider. At least maybe 4 of them. Thanks! __________________

05-02-2012, 12:54 PM	#12 (permalink)
Dean W. Dean W.'s Photo Gallery Location: Cedar Park, TX Zone: 8b Join Date: Sep 2007 Posts: 4,279 BananaBucks : 234,340 Feedback: 13 / 100% Said "Thanks" 6,325 Times Was Thanked 2,130 Times in 972 Posts Said "Welcome to Bananas" 300 Times	Re: Arbor/ Trellis design questions Hey GreenFin, Yes, I planted those bushes there years ago that act as a wind screen from the North and also provide some privacy. I went ahead and bought 6-4x4s as per the suggestions I got here. I'll use the 2x4s as cross supports. Already got two holes dug 18-20" deep so I just need to dig 4 more. Then I'll need to line them up and level them a bit. It's a little difficult because it's on a slight hill. So I may use a string with a level. Thanks for everyone's suggestions. I should have listened the first time, but sometimes we don't want to hear the truth I guess. __________________

05-02-2012, 01:55 PM	#13 (permalink)
GreenFin Location: Kansas Zone: 6a Join Date: Jan 2012 Posts: 595 BananaBucks : 87,575 Feedback: 0 / 0% Said "Thanks" 1,396 Times Was Thanked 939 Times in 334 Posts Said "Welcome to Bananas" 44 Times	Re: Arbor/ Trellis design questions That thing might be hurricane-proof by the time you're done with it __________________ Set out runnin', but I'll take my time; a friend of bananas is a friend of mine. www.GreenFinGardens.com

05-02-2012, 05:49 PM	#14 (permalink)
Scuba_Dave Location: South of Boston, MA Find me on the map! Zone: 6-7 Name: Dave Join Date: May 2009 Posts: 732 BananaBucks : 58,442 Feedback: 0 / 0% Said "Thanks" 501 Times Was Thanked 1,218 Times in 451 Posts Said "Welcome to Bananas" 2,414 Times	Re: Arbor/ Trellis design questions I actually have over a dozen "spare" PT 4x4's & a few 4x6's I've taken down 2 pool decks that people were getting rid of & reclaimed the wood On my greenhouse instead of attaching the 2x4's width to width to make a 4x4 I made an L shape at the corners with the 2x's __________________ .

05-03-2012, 02:27 PM	#16 (permalink)
Dean W. Dean W.'s Photo Gallery Location: Cedar Park, TX Zone: 8b Join Date: Sep 2007 Posts: 4,279 BananaBucks : 234,340 Feedback: 13 / 100% Said "Thanks" 6,325 Times Was Thanked 2,130 Times in 972 Posts Said "Welcome to Bananas" 300 Times	Re: Arbor/ Trellis design questions Finally got the 4x4s in the ground. It may get a little shade in the late afternoon, but I think I should be able to grow them here. Need to nail the 2x4s atop this thing and prepare the soil. __________________

05-05-2012, 11:42 PM	#18 (permalink)
Olafhenny Olafhenny's Photo Gallery Location: Penticton, BC, Okanagan Valley, Canada Find me on the map! Zone: Hardiness Zone 6 Name: Olaf Join Date: Apr 2010 Posts: 1,705 BananaBucks : 245,980 Feedback: 0 / 0% Said "Thanks" 2,050 Times Was Thanked 2,012 Times in 876 Posts Said "Welcome to Bananas" 77 Times	Re: Arbor/ Trellis design questions Sorry, Dean, I am a bit late, but it looks, like you need a bit of engineering advise. As your structure stands now, I disagree with Scuba Dave that it will blow over at 40 to 50 mph winds. If you put anything on it, which will catch the wind, such as vines, it will blow over at less than 20 mph. Your joints at the corners will act like hinges and make the structure fold like a card house, digging the posts deep will help a little, but not enough. The very least you will need is diagonal cross strapping. No need to do it across the whole span of the beams. 3 feet x 3feet from the cross beams to each post will give it plenty of stability. But if you want that structure to stand up for 10 years or longer, I am afraid you will have to start from scratch: Dig the post holes about 1 foot deep and at a diameter of about 8 to ten inches. Important is, that the walls of the holes are undisturbed soil (no lose dirt). Fill the holes with ready mix concrete. You will need a bag for each 2 to 3 holes. Into that concrete you plant a post bracket for each post as you see in the top left corner of this site: post base brackets - Google Search Make sure these brackets are lined up, sighting from post to post. Having them all the same elevation will help too. You can ensure that, by using a carpenter’s level and the straightest one of your 2x4s for the top frame to get them all to the same height. The idea of the brackets is, that you do not want to have direct contact between concrete and wood, no matter how well the wood is treated, incised or otherwise. Concrete will make and wood rot prematurely. Another bit of advise: Don’t torture yourself by using nails. Beg, steal, borrow or rent a cordless drill and use 3” special screws for treated lumber. The job will go twice as fast and will require a lot less foul language to get it done. Good luck, Olaf PS: I am adding a couple of pictures from my own gazebo construction eight years ago. You can see, I kept the diagonal strapping a bit shy, but I could afford that, because of the diagonal grid of all the minor straps. This is an attempt to blow up part of the previous picture to show the post sitting in the bracket, which in turn sits in the concrete. It is important, that the concrete is right against the base of the bracket, for stability, but does not touch the wood. __________________ The reason I joined this forum was to share experiences, my own and those of others and to learn from them.

05-06-2012, 12:05 AM	#19 (permalink)
sunfish Banned sunfish's Photo Gallery Location: San Diego Find me on the map! Zone: 9-11 Name: Tony Join Date: Apr 2008 Posts: 18,429 BananaBucks : 945,900 Feedback: 8 / 100% Said "Thanks" 3,210 Times Was Thanked 20,591 Times in 7,760 Posts Said "Welcome to Bananas" 2,716 Times	Re: Arbor/ Trellis design questions Use galvanized steel post 2' in ground and carriage bolts it will last 100 years

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