What concrete blocks for compost heap?

[DuncanM]

Without going down the route of "why are you using concrete blocks", I'm after a bit of advice about which would be best.

I can see there are generally 3 varieties; aerated, medium density and solid.

The price for all three is pretty similar, but the advantages / disadvantages I can see:

Aerated / lightweight - much easier to handle, have good insulation values (which may help keep the compost warm). However I don't know if they'd chip/crumble in such close proximity to spades and forks? If it's only the odd chip I wouldn't mind, but if it were more severe I'd think about not using them.

solid / dense - much heavier so more difficult to handle, don't offer any real insulation value, but would be much less prone to any chipping from accidental tool strikes.

The medium density obviously sit somewhere in the middle of the park.

thanks

[alldigging]

Nah got to do it:
Why go down the route of using concrete blocks?

I've seen breeze blocks used for building "bins" for muck and bark.

The heavy ones will be very dangerous if they fall over, the lighter ones still going to hurt toes.
Are you planning on cementing them together?

[arpoet]

In my book i would save me money and site my compost on bare soil.

[alldigging]

https://www.youtube.com/watch?v=Ce7IVl-glaQ

[Bigmallly]

Sorry Duncan but I have to agree, save your money & source some pallets.

[Potstubsdustbins]

Whilst I agree with the above in answer to your question the light weight insulation blocks are made for internal non load bearing applications only.

They will be quickly affected by the weather and are prone to crumbling.

[DuncanM]

It would be sited on bare soil. There'd be a small trench to support the blocks.

Personal choice... the compost bins on the plot have been getting worse and worse the 3 years I've had the plot (and they were in bad shape when I first started). I've tried builders bags supported with pallets in the past and I'd much prefer something I can easily push and tip my barrow in. I don't fancy the route of doing it with solid pallets then having to re do it all again at some point in the future..maybe 10 years? I don't know.

What I've planned will cost me approximately £50, so it's not outrageously expensive, however I do know a lot of people prefer to run their allotment on entirely recycled materials.

I haven't decided if I'd be mortaring them together or not. I'd decide when I'd bought them and played around to see the stability of them loose.

[alldigging]

Anything you're planning on running a wheelbarrow into will need to be solid enough not to fall down.

[Bigmallly]

Duncan - Just wondered if some of these fastened to 4 posts would be easier to build plus has a 15 year weathering guarantee.

Black Corrugated Bitumen Sheet 950x2000mm | Wickes.co.uk

[Kristen]

I'm never quite sure how much air a compost heap needs

When i've built decent sized ones I used weather-board, and left some gaps between them (for air).

Daleks are solid plastic, so don't have air gaps.

Monty D's are corrugated iron,a nd huge, so not much ingress of air.

My Weatherboard heap was built for 10 years before we moved property and was still going strong at the end of that - the boards would have been "treated". Dunno if that would be a suitable alternative to blocks? I constructed it so that the front face could be removed piece-meal - two posts [at front left & right corners] that the boards dropped in inbetween, and each had a spacer on the bottom to create a gap. Made it easier to fill - add a board as the level rose, and to empty - remove the boards, and then excavated the contents.

But if pallets are readily available I don't think it matters if they don't last very long - strapping there new replacements together for the sides will only take a few minutes.

[DuncanM]

I appreciate the suggestion Bigmally but having used those sheets to build the roof for an enclosure for my sister-in-laws ducks, I wouldn't trust them to last a year in constant contact regardless of guarantees.

Time is more of an issue than money (not that I have money to burn, but I feel it's reasonable, as the most likely last bit I need to spend money on my plot). I would need to source, transport then sort the pallets out, and I don't know how long it'd take to source pallets or what size they'll be. For the blocks, I can pick them up and lay them all in one day.

[crannman]

become a skip monster ask first lots of old building material

[veggiechicken]

Sounds like you've made your mind up on concrete blocks Duncan!!
Doesn't sound very safe to me, if you're just going to stack them on top of each other
What about setting up 4 posts at the corner and wrapping wire netting around 3 sides, with a removable panel on the 4th side. Cover the top with a bit of carpet or tarpaulin.

[arpoet]

I have 3 unproductive areas for hos much, but use daleks for garden and kitchen waste. I like the idea that i can just remove the dalek when its full and need turning and just fork into another space. I have 3 dotted about under trees where nowt else will grow.

[Bill HH]

Building them loose would definately demand the heaviest block. But how do you build them loose? because you will need to stagger the joints for stability which means starting every other row with a half block. Without cement that will just fall out. Do it right with a footing and mortar the blocks, also add a cement cap to stop rain filling the holes and blue tits nesting in them. Make it big and one day you could add a roof and move in or have some pigs.

Your reason for not doing it in wood is ok, but blocks dont last forever in that situation, They get soaked without a roof and moss covered then the frost breaks them up.