Height restricted hydroponic loft grow

[Blue brother]

I'm in the planning stage of converting a loft, right now it has no floor or walls and the roof rafters are all exposed.

We're gonna clear it all out, lay some tongue n groove weyroc flooring, install 2 steels between load bearing walls to hold a 600-750l reservoir, insulate the roof and board it all out with Osb sheets, Bring up power from a cooker socket below, 30Amp 240v, bring up water from the bathroom and install a tap, and branch into the soil stack as a means of disposing our waste water.

When this is finished I'll have a room measuring 3.3mx4.6m. The walls will come up 1m from the ground before hitting the roof, from the top of the wall to the top of the roof measures 1.9m from the top of the wall to the peak. The Osb walls and ceiling will be lined with panda film.

There will be 2 rows of 3 bar style LEDs hung at a height of 1.3m, I've got 4 allready ranging from 800w to 1000w that I'll use for now and I'll grab another 2 once the build is complete.

Ventilation will be 2 12 inch ac infinity fans with a 12 inch mountain air filter each, I've got a controller 69 pro right now but I'll maybe upgrade to the controller ai pro by the time it's set up. I've got 2 40lpd dehueys and various humidifiers but I'll probably upgrade those to one big humidifier.

For this new room I'm going back to my roots, glorious grodan will be the substrate. I chose hydro cos I don't think the weight of huge pots and beds of living soil is a good idea in the loft as it doesn't have a proper floor, it's just the ceiling joists, they reccomend no more than 50kg per metre squared static weight, of course you can walk around up there periodically but just can't store anything over 50kg per metre.

There are two load bearing brick walls that finish under the ceiling joists, I'm gonna span a couple of box lintels diagonally between them and this will hold a 600l flexi tank.

So from the floor to the top of the plant must be under 1m ( the highest I can hang the LEDs is 1.3m from the floor to give even coverage) I've grew plenty plants this size before that have given me great yields when trained right.

So now I'm looking at what kind of system I can build/buy. I'm leaning towards using Hugo blocks and grodan slabs ontop of perhaps a danish tray or in aqua trays designed for the slab.



I'll be using drip irrigation and I love the look of all the flora flex stuff. When I grew in rockwool I just used the 2lph drippers, 2 per block, tbe trays were on tables and would just gravity drain back into the res. Height unfortunately won't allow that here so I'll be using one of those fancy condensate/sump pumps with the float valve to return run off to the tank.

Im reading a lot about crop steering and low volume high frequency irrigation by using rootzone meters and solenoids, but in all honesty I'll probably just use a smart timer and figure my irrigation out through trial and error, I used to do 8 irrigations a day and just tailor the feed time to how the plants responded, I've even had good results running them 24/7 believe it or not.

I used to do hempy buckets with grodan cubes and blocks back in the day and they were so simple, at first I hand watered, then I built some drip rings and fed them once a day on a timer.



So what do you guys think? I'm all ears!

On the construction side of things I don't really need any pointers as that's been my job for 20 years so I know what I'm doing and I've got trusted friends who are also in the biz. But by all means if you think I'm missing something let me know.

Mainly I just wanna know if anyone's done grows with this kind of height restrictions before and how did it go, what system did you use?

And anyone who's clued up with all this new irrigation tech and these condensate style return pumps, crop steering, know of any cheaper alternatives to a full grosens kit?

I don't really wanna go over 24 plants in this space so that works out about 2 per square meter.

has anyone grown 1m square plants in blocks and slabs? I've done them in Hempys and buckets of mini cubes with flood n drain and drip but never in a block.

Also if anyone has any input about where I should place my equipment in the room?
I'm tying to take advantage of all the space above the lights, this is where I'll hang my filter. I would've liked to get my dehumidifiers up here too but doubt they'd make much of a difference to canopy level humidity all the way up there.

Sorry this is such a long opening post but there was a lot to cover

Thanks in advance for taking the time to read this and I appreciate your feedback!

Blue

 

[Absorber]

Do you plan on not using the stove downstairs anymore?

 

[Blue brother]

Do you plan on not using the stove downstairs anymore?

The stove doesn't get used it's, not even wired up anymore it's just there for show haha

 

[Absorber]

The stove doesn't get used it's, not even wired up anymore it's just there for show haha

Ok ,thats good.
If i had the same height resrictions id probably just run with the SOG(sea of green) method . You just have to have lots of clones each run and just flip them straight away and create a sea of cola's.

 

[Blue brother]

Ok ,thats good.
If i had the same height resrictions id probably just run with the SOG(sea of green) method . You just have to have lots of clones each run and just flip them straight away and create a sea of cola's.

Yeah that's a wonderful idea and I wish I could but unfortunately it's a plant count issue. I'll be topping a branch before I clone it, then I'll kinda mainline it to make 2 main branches, the plants canopy shape will be a rectangle to fill a 50x100cm space, I had thought about doubling the plant count to 48, but that would work out at over 100 plants including what's vegging and what mothers I have

 

[coreywebster]

Well it sounds like a cracking plan dude.
Looking forward to seeing it come together.

Can't add much value to this conversation, I first started growing long ago with NFT and that's kind of like those Danish trays , but you have capillary mats instead of rockwool slab.
You have constant water flow with that method and I don't see how it would be detrimental in your case either..


I think youl know more than me, being in the trade, but wouldn't osb eventually swell from the RH?

Would it not be a better idea to seal it with zinser or something white and water resistant rather than line it out with panda?

Just thinking long term.

 

[Blue brother]

Well it sounds like a cracking plan dude.
Looking forward to seeing it come together.

Can't add much value to this conversation, I first started growing long ago with NFT and that's kind of like those Danish trays , but you have capillary mats instead of rockwool slab.
You have constant water flow with that method and I don't see how it would be detrimental in your case either..


I think youl know more than me, being in the trade, but wouldn't osb eventually swell from the RH?

Would it not be a better idea to seal it with zinser or something white and water resistant rather than line it out with panda?

Just thinking long term.

Yeah ur absolutely right bro it will be getting sealed with something but I'm currently speaking with my painter friend about which to use, I don't think it needs a full on seal like bitumen paint but I also don't think something like a bathroom paint will cut it, although we've done plenty loft conversions etc, this for me is uncharted territory, I've never built a room for a grow in a loft, obviously there's gonna be a lot of water and opportunity for condensation to form, even though we're thoroughly insulating the roof I've seen condensation form on insulated bedroom walls.

I am however fully sealing the walls with panda film and siliconing all corners and edges which should somewhat mitigate wet air making contact with the Osb.

I hadnt actually considered nft but because of its low profile its a good option I'd just have to match the return pump to the feed pump and it would work lovely, because unfortunately I'll still need the res to be elsewhere as I can't have too much weight permanently on the floor.

This is my first time using a pump for run off like this and tbh it's pretty daunting, whatever I decide with them I'll probably buy 2 and run them both in the same bucket or tub or whatever, just incase 1 breaks and a flood brings the ceiling down haha. I've allways built systems where the plants are elevated higher than the res and gravity takes care of the return

 

[OneHitDone]

@Blue brother being that this is a fresh build, is there any way you could incorporate drains for the trays into the floor avoiding the need for the condensate pumps? Being in a loft I would be paranoid a pump may fail and back up / overflow into the ceiling.
I am currently intentionally growing a bit height restricted with a double stacked system using aero/hydro rails and condensate pumps with the reservoirs located outside of the grow chambers.

 

[Blue brother]

@Blue brother being that this is a fresh build, is there any way you could incorporate drains for the trays into the floor avoiding the need for the condensate pumps? Being in a loft I would be paranoid a pump may fail and back up / overflow into the ceiling.
I am currently intentionally growing a bit height restricted with a double stacked system using aero/hydro rails and condensate pumps with the reservoirs located outside of the grow chambers.

I'm not quite sure I get what you mean matey, do you mean put my res on the floor below the loft and feed up through the ceiling and drain back down through the ceiling? Or do you mean do drain to waste? Like dispose of the runoff?

If it was the first, I can't do that it's my living room haha. The whole point of moving my op into the loft is to have it all out of sight.

If it was the second then yeah but I had considered running the drain from the trays straight into the soil pipe. I did do drain to waste maybe 10 years ago and had good results, but I do prefer recirculating in hydro, maybe my mind can be changed through the course of this build, I see more and more pros doing drain to waste these days but they usually have substrate ec and ph meters. It's certainly not something I wouldn't do.

 

[OneHitDone]

I'm not quite sure I get what you mean matey, do you mean put my res on the floor below the loft and feed up through the ceiling and drain back down through the ceiling? Or do you mean do drain to waste? Like dispose of the runoff?

If it was the first, I can't do that it's my living room haha. The whole point of moving my op into the loft is to have it all out of sight.

If it was the second then yeah but I had considered running the drain from the trays straight into the soil pipe. I did do drain to waste maybe 10 years ago and had good results, but I do prefer recirculating in hydro, maybe my mind can be changed through the course of this build, I see more and more pros doing drain to waste these days but they usually have substrate ec and ph meters. It's certainly not something I wouldn't do.

I was assuming you were doing drain to waste and sending the runoff down the sewer

 

[Blue brother]

@coreywebster I'm going with zinser watertight

I was assuming you were doing drain to waste and sending the runoff down the sewer

ah no mate, when I empty a res or pre soak anything, Thatl be going down the branch to tbe soil pipe, I might actually put a little sink in there for washing my hands and pouring stuff down this will be outside of the grow room though.

Sorry mate I better mention, those plants look fantastic by the way, did you build those rails yourself?

 

[coreywebster]

@coreywebster I'm going with zinser watertight

ah no mate, when I empty a res or pre soak anything, Thatl be going down the branch to tbe soil pipe, I might actually put a little sink in there for washing my hands and pouring stuff down this will be outside of the grow room though.

Sorry mate I better mention, those plants look fantastic by the way, did you build those rails yourself?

Good choice!

They've got a coating for everything ..


One of the best things I did in my current place was install a sink.

Though couldn't get hose to seal nice so ended up putting a washer supply on the cold water pipe too.

 

[Blue brother]

Good choice!

They've got a coating for everything ..


One of the best things I did in my current place was install a sink.

Though couldn't get hose to seal nice so ended up putting a washer supply on the cold water pipe too.

Yeah mate I've wanted a sink for aslong as I've grown, I remember reading a tutorial one time when I was younger and it was saying to choose an old bathroom or kitchen to grow in. Now I'm grown and realise bathrooms are small and kitchens are usually downstairs and have a door to outside I'm not sure it's solid advice but the water supply is certainly a plus.

Hey man those fans are still going strong screwed to my ceiling facing down, who would've thunk it Hahaa, good looking out bro!
I was sitting thinking about how glad I am I've found reliable fans that I can screw to the sloped Osb ceiling of my new room without worry of having to keep getting in and changing tbem when they inevitably break mid cycle