…… Durock concrete backer boards as raised garden beds

[Toosh]

I’m looking to replace 7 year old pressure treated raised beds. Current beds are 3’ x 10.’ I would like to stay close to that. I have access to a bunch of free durock concrete backer boards. They are ½” thick, 3’x5’ boards. What I have in mind is to rip them 18” tall, 5’ long. I’m thinking about doubling them to 1" thick because I think that is needed to support the weight of soil. I plan to join two lengths to make a 10’ bed.

Questions:

• Is this product feasible for this application? It seems like a genius idea to this blond so why have I not seen it done before?
• I assume it won’t rot but will it erode from wet soil/water?
• Better to join two boards to 1”thick with exterior block adhesive or concrete?
• Will water getting between panels erode them? Should I fill the top seam where I double the thickness with concrete?
• Should I skim coat the sides or will the backer board be damaged by string trimmer? By burning weeds with a torch?
• How should I join the corners? I’m trying to stay away from wood.
• Can I span 5’ if I go 1” thick?
• Other concerns I haven't thought of? Suggestions?

Yes, yes, I know I can use concrete blocks but did I mention the backer boards are free?

 

[Raggedyman]

Toosh
I would think that Durock would be slowly eroded to crumbly nothingness just as hardie board can be if it sits in constant wet and dampness. painting it might help - but IMHO you'd be much better off with concrete block. you could fill the cells with gravel which would help to retain some moisture as well as keep them from moving so much

 

[Dux]

Genius. They are used for tiling over tub surrounds.

 

[tom-j]

Better to join two boards to 1”thick with exterior block adhesive or concrete?

I would use thinset to join them.
Thinset is the cement mixture used to cement durock to floors and to cement tiles to durock.

 

[OldAndCrazy]

Bad idea. They'll fall apart quick and it's very expensive for what you get. Stick with the advice above and get the cement block.

 

[mecoastie]

I dont think it will work long term. It will erode and break down fairly quickly and if you hit it with anything like shovel digging you are going to chip/damage it.

 

[West]

Since there free, experiment with a couple boards. Build only a 5x5 raised bed out of them. Or double them up.

I would recommend to backfill dirt around the raised bed for support on the outside at the same level of the inside.

Likely the boards would crack then fail under the stress of dirt in the raised beds.

However if backfilled maybe not or if it does last years, the additional dirt on the outside would help with water retention and future soil that you could use later.

 

[kyrsyan]

Continual exposure to wet and weather will disintegrate them.
As an alternate idea, look up using IBC totes as raised beds. Due to a number of issues here, I am starting the first ones this year. Although I'm add a wicking chamber and middle layer of tree limbs.

 

[ioujc]

Saw a YouTube on this.....he cemented the outsides of 2 pieces which had been glued together.....did it for all 4 sides and joined with L-braces....looked like it worked for him.

 

[China Connection]

Durock® Brand Cement Board with EdgeGuard™ | USG

Durock® Brand Cement Board with EdgeGuard™ offers enhanced, proprietary edge performance, preventing spinout and crumbling.

www.usg.com

 

[China Connection]

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