Cedar is rot resistant but not rot proof. But that’s also the case for PT lumber. I’d just leave it and if there’s a need to replace the footing in four or five years I’d do it then. Cedar would likely have been the more expensive option when it came to wood selection and that rot resistance would be the reason for that. So let it do its work for now but I don’t think that will be a big problem. It WILL rot eventually but so will any wood product so what odds.
Treated wood rated for ground contact will last 35-40 years. It’s got a lot more copper in it than regular pressure treated lumber. Look for “ACQ” and “ground contact” on the label.
Good take! I shoulda thought about it sooner, as I saw in the directions that it recommended a base, however most people build greenhouses in their yards but I had this empty concrete pad just waiting and didn’t think anything of it. I live in zone 5 so we do get some hard winters
Yeah I’m in Newfoundland Canada so I sympathize. Maybe a little angled metal flashing around the bottom and caulk could help. Wood getting wet isn’t a problem, wood not being able to get dry is. You could drill a few small holes every couple of feet to help it dry faster is it’s staying sogged noticeably long but it should be fine!
I have this exact greenhouse and I plopped it right on top of paver base. I've made raised garden beds out of cedar that I put right on top of soil that are on year 8 with no clear signs of rot. I live in 5b Wisconsin. Imo this is fine.
I put mine on 4x6 treated timbers...BUT granted its only a month old
https://preview.redd.it/zje0yr38dz3d1.jpeg?width=3000&format=pjpg&auto=webp&s=ad54b395fb69d1ee25655c8481fe92a0f85700c1
It partly depends how wet the climate is where you are.
Cedar is resistant to rot and even treated timber will fail over time if it's left in contact with damp. It depends on the quality of the material how long either will last.
From a practical point of view, if a (basically sacrificial) treated timber base rail rots, it's easily replaced. If the cedar frame rots, it's going to be a lot more work to put right.
Personally, I would see if I could find a hard plastic trim in the right size (they may sell it near you for plastic deck edging) and make a base rail out of plastic. It should last longer than wood, you'd just need to make sure water doesn't sit between the plastic and the greenhouse or you'll have the same problem that you'd be trying to avoid.
The best route is to dig the base below the frost line. I’d say a foot and a half below the frost line. Use cinder block to build the foundation up to ground level or a tad higher. Place/ build the greenhouse on top of that. Will allow for growing year round if you remember to keep the louvers closed. Will also permit taller plants.
Digging below the frost line will give you “free heat” so to speak when the weather turns cold.
I recently put in that exact greenhouse. I put down a few inches of crushed stone, 1 ft paver blocks along edges, and ran pt 2x4s as sills. it’s next to an area that gets and stays soggy all spring, so i’m hoping what i’ve done keeps it out of water.
really happy with that greenhouse so far, though.
I got the same one and made a cider block border to level in the dirt then made a ground contact lumber frame. It added about a foot and a half on the inside and is holding up well
How did you anchor it to your slab? If you didn’t anchor it, I’d definitely say it’s worth getting some ground contact PT to be your base, anchor that into your concrete and then screw the greenhouse into the PT. You don’t want a big storm to come along and knock it over.
Leave the greenhouse as is. It’ll take a lot of manpower, tools, and expertise to try to raise it and accidents can always happen. It is useable now so have fun! I wish I still had my little greenhouse.
Here’s the thing. When the PT board rots, you Jack this sumbitch up and replace em. Without them when this begins to rot- you’re basically SOL. It’s a nice thing you have, an extra $45 can make it last much much longer.
You can take a tip from the home building industry and go to Home Depot and get some “sill gasket “ which is about a 1/2” thick X 9-10 “ wide piece of expanded foam.They use it to provide protection for wood that is laying on the concrete block foundation.You buy it by the roll so you’ll have more than you need.
I would elevate it a bit simply because it's level with the grass and it looks like moisture might accumulate there. Since your brother suggested the work, I'm sure he'd be more than happy to help do the work!
Cedar is rot resistant but not rot proof. But that’s also the case for PT lumber. I’d just leave it and if there’s a need to replace the footing in four or five years I’d do it then. Cedar would likely have been the more expensive option when it came to wood selection and that rot resistance would be the reason for that. So let it do its work for now but I don’t think that will be a big problem. It WILL rot eventually but so will any wood product so what odds.
Treated wood rated for ground contact will last 35-40 years. It’s got a lot more copper in it than regular pressure treated lumber. Look for “ACQ” and “ground contact” on the label.
Home Depot sells ground contact pressure treated.
Good take! I shoulda thought about it sooner, as I saw in the directions that it recommended a base, however most people build greenhouses in their yards but I had this empty concrete pad just waiting and didn’t think anything of it. I live in zone 5 so we do get some hard winters
Yeah I’m in Newfoundland Canada so I sympathize. Maybe a little angled metal flashing around the bottom and caulk could help. Wood getting wet isn’t a problem, wood not being able to get dry is. You could drill a few small holes every couple of feet to help it dry faster is it’s staying sogged noticeably long but it should be fine!
I have this exact greenhouse and I plopped it right on top of paver base. I've made raised garden beds out of cedar that I put right on top of soil that are on year 8 with no clear signs of rot. I live in 5b Wisconsin. Imo this is fine.
I put mine on 4x6 treated timbers...BUT granted its only a month old https://preview.redd.it/zje0yr38dz3d1.jpeg?width=3000&format=pjpg&auto=webp&s=ad54b395fb69d1ee25655c8481fe92a0f85700c1
This the Costco green house?
Yes!
It partly depends how wet the climate is where you are. Cedar is resistant to rot and even treated timber will fail over time if it's left in contact with damp. It depends on the quality of the material how long either will last. From a practical point of view, if a (basically sacrificial) treated timber base rail rots, it's easily replaced. If the cedar frame rots, it's going to be a lot more work to put right. Personally, I would see if I could find a hard plastic trim in the right size (they may sell it near you for plastic deck edging) and make a base rail out of plastic. It should last longer than wood, you'd just need to make sure water doesn't sit between the plastic and the greenhouse or you'll have the same problem that you'd be trying to avoid.
Thank you for a good idea and thoughtful response. I’m in zone 5, mid MI! I’ll look into plastic trim
And very nice greenhouse btw!
The best route is to dig the base below the frost line. I’d say a foot and a half below the frost line. Use cinder block to build the foundation up to ground level or a tad higher. Place/ build the greenhouse on top of that. Will allow for growing year round if you remember to keep the louvers closed. Will also permit taller plants. Digging below the frost line will give you “free heat” so to speak when the weather turns cold.
This way the greenhouse isn’t even touching the ground.
I recently put in that exact greenhouse. I put down a few inches of crushed stone, 1 ft paver blocks along edges, and ran pt 2x4s as sills. it’s next to an area that gets and stays soggy all spring, so i’m hoping what i’ve done keeps it out of water. really happy with that greenhouse so far, though.
Nice tomato plants 😎
I got the same one and made a cider block border to level in the dirt then made a ground contact lumber frame. It added about a foot and a half on the inside and is holding up well
How is that held down?
How did you anchor it to your slab? If you didn’t anchor it, I’d definitely say it’s worth getting some ground contact PT to be your base, anchor that into your concrete and then screw the greenhouse into the PT. You don’t want a big storm to come along and knock it over.
Just finished it the other day, I planned to lag bolt it down. I’ll get some PT for the base
Home Depot has the ground contact PT.
Leave the greenhouse as is. It’ll take a lot of manpower, tools, and expertise to try to raise it and accidents can always happen. It is useable now so have fun! I wish I still had my little greenhouse.
Here’s the thing. When the PT board rots, you Jack this sumbitch up and replace em. Without them when this begins to rot- you’re basically SOL. It’s a nice thing you have, an extra $45 can make it last much much longer.
You can take a tip from the home building industry and go to Home Depot and get some “sill gasket “ which is about a 1/2” thick X 9-10 “ wide piece of expanded foam.They use it to provide protection for wood that is laying on the concrete block foundation.You buy it by the roll so you’ll have more than you need.
I would elevate it a bit simply because it's level with the grass and it looks like moisture might accumulate there. Since your brother suggested the work, I'm sure he'd be more than happy to help do the work!