New build loft

S

SmokinTheHerb

Active Member
Hey hey all,

Grew a few grows back in 2014 but had to pack it in due to the situation at home with my ex. Got police to my door more than once with the tent up and they even found it but thankfully I’d held off planting both times and got away with it.

The paranoia set in thereafter and I didn’t set anything up for as long as I’ve been in rentals.

Now I have moved into a new build property and after popping my head into the loft space my mind immediately got to work thinking about how I could get my 1.2x1.2 tent up.

I’m aware that to grow in the loft I’m going to need to handle insulation. There’s loads up there now on the floor (easily 280-300mm) so that much should be fine.

Thinking of using the LoftZone product to build a raised floor platform over the insulation ensuring plenty space for air under the floor itself.

Will put insulation into the roof between the rafters and seal over that to ensure no heat escape through the roof itself.

Now I know that new builds are not built like homes used to be and it’s probsbly not got a lot of spare support for the weight of the Wilma res and a water butt.

I don’t want to raise my queries with building control as this is really not something I want to publicise that I’m doing.

Basically is there anyone who is a structural engineer and could advise how I could go about strengthening the floor?

I can try to get some pics up this week if it would help. All I’ve seen so far is there is a lot of insulation and knowledge of new builds tells me I’ll have to strengthen it up.
 
Renfro

Renfro

Well-Known Member
Well I am not an engineer but I would say that you could sister some joists up to the existing ones, making them into LVL's. For example, lets say you have a 2x8 inch joist. You buy another piece of 2x8 lumber and cut to the same length. You take and sandwich a piece of 3/4" plywood cut to fit between them in strips length wise. So you have -> Existing Joist + Plywood + New Sister Joist.. Using construction adhesive between layers and lag bolts so sandwich the layers (use washers on the lag bolt heads to prevent pull through)

That is one way to really strengthen a span.

It can be difficult as sometimes wiring is in the way and needs to be pulled out and put back after because you don't want to split the beam you are adding.

Another way is to reduce the span of the joists with a column. That requires a brace perpendicular to the existing joists, say in the middle of the span, then you support that with a column on each end and the center if the perpendicular column is long.

To test your load capacity you can hang a plumb bob from the center of the span and make it so it's 1/4" from the floor and put a load on the floor directly above it, say a water barrel with a drain valve. Fill the barrel with a hose and watch the plumb bob and see when the deflection is 1/4" or more.

I hope all that helped.
 
Rainbow Warrior

Rainbow Warrior

Well-Known Member
SmokinTheHerb said:
Hey hey all,

Grew a few grows back in 2014 but had to pack it in due to the situation at home with my ex. Got police to my door more than once with the tent up and they even found it but thankfully I’d held off planting both times and got away with it.

The paranoia set in thereafter and I didn’t set anything up for as long as I’ve been in rentals.

Now I have moved into a new build property and after popping my head into the loft space my mind immediately got to work thinking about how I could get my 1.2x1.2 tent up.

I’m aware that to grow in the loft I’m going to need to handle insulation. There’s loads up there now on the floor (easily 280-300mm) so that much should be fine.

Thinking of using the LoftZone product to build a raised floor platform over the insulation ensuring plenty space for air under the floor itself.

Will put insulation into the roof between the rafters and seal over that to ensure no heat escape through the roof itself.

Now I know that new builds are not built like homes used to be and it’s probsbly not got a lot of spare support for the weight of the Wilma res and a water butt.

I don’t want to raise my queries with building control as this is really not something I want to publicise that I’m doing.

Basically is there anyone who is a structural engineer and could advise how I could go about strengthening the floor?

I can try to get some pics up this week if it would help. All I’ve seen so far is there is a lot of insulation and knowledge of new builds tells me I’ll have to strengthen it up.
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Renfro summed up the whole structural side of things. That’s the easy part
Your no 1 problem is, like hotrodharley says, heat. Being a plumber, I’ve been working in enough lofts over the years and I don’t know anywhere that gets as stifling as a loft in summer; I’m talking 40 degrees+, enough to keep sweat running down anyone’s crack ;-).
I’m using my old chickenshed, insulated with 6” polystyrene. Keeps the room cool, but it only works coz night time temps are dropping; they won’t really do that in your loft. I wouldn’t even consider using your loft (keep heat seeking Helicopters in mind also); i heard of people getting busted coz grow lofts are often the only ones without snow on the tiles.

You could super insulate, but that won’t stop the heat eventually building up and it will keep the cold in.

Unless you have proper access it’s a pain in the arse getting up there once or twice a day to keep an eye on things and tweak ur system...

RW
:peace:
 
S

SmokinTheHerb

Active Member
Hey renfro,

Thanks for the advice on the structural aspect. I’ve seen this in some other posts and it’s the route I think I’ll look into first.

I’m in no immediate rush. I’ll take my time and plan well and only go for it when everything is good.

Good shout regarding testing the load capacity with a plumb bob. I will give this a go.

Would you expect the results to be fairy instant or would it be worth repeating it a few times over say a week or two with the load in place?


Hey hotrodharley,

In terms of the environmental heat in the loft my idea was to initially floor it with the 300mm insulation in place underneath the flooring. That tackles heat rising from the house.

Next step would be to insulate the entirety of the roof.

Finally I would build a stud wall room inside the space which is insulated itself.

Within this room I’ll have my tent set up and room for an AC unit to cool the inner room itself.

I’d hope that I could exhaust the excess hot air out by the eaves as these modern houses really can’t take a hot outtake into the rooms.

Alternatively perhaps put a boiler looking vent in and exhaust from there.

Unfortunately no chimney stack in these new builds as they don’t put in fireplaces.


Hey RainbowWarrior,

Valid point on the chopper front.

I’d hope that if I can get the room fully insulated properly then it shouldn’t really cause any snow to melt or even any sign of anything going on within.

The hot air exhaust will look out of place though almost certainly.

I’ll need to give that aspect of it a lot of thought.
 
S

SmokinTheHerb

Active Member
Quick update.

Ripped all the insulation out of the loft to get a good look at things.

Theres a good amount of space there to work. I can get water from the bathroom below and there is a 5-inch vent in the roof for the bathroom extractor fan which I can try out hooking up my rhino fan to see if I’ll need anything more powerful/larger.

Worked out that my joists are around 1.5 x 3.5s, so pretty damn awful. Got 2x5s sistered in with some help and it’s gone from not great to walk on to being rock solid.

Need to get all the insulation back in and then I’ll look at a raised floor over the insulation.

Once that’s done it should be solid enough to set up and heat test.

Also, traced where the power cables go down to the consumer unit so that I can put in some new circuits for this.

Definitely coming along slowly but surely.
 
Renfro

Renfro

Well-Known Member
SmokinTheHerb said:
Quick update.

Ripped all the insulation out of the loft to get a good look at things.

Theres a good amount of space there to work. I can get water from the bathroom below and there is a 5-inch vent in the roof for the bathroom extractor fan which I can try out hooking up my rhino fan to see if I’ll need anything more powerful/larger.

Worked out that my joists are around 1.5 x 3.5s, so pretty damn awful. Got 2x5s sistered in with some help and it’s gone from not great to walk on to being rock solid.

Need to get all the insulation back in and then I’ll look at a raised floor over the insulation.

Once that’s done it should be solid enough to set up and heat test.

Also, traced where the power cables go down to the consumer unit so that I can put in some new circuits for this.

Definitely coming along slowly but surely.
Click to expand...
Now is the time for lots of planning. Sounds like you are off to a good start. We are here to help.

bongsmilie
 
hotrodharley

hotrodharley

Well-Known Member
SmokinTheHerb said:
Quick update.

Ripped all the insulation out of the loft to get a good look at things.

Theres a good amount of space there to work. I can get water from the bathroom below and there is a 5-inch vent in the roof for the bathroom extractor fan which I can try out hooking up my rhino fan to see if I’ll need anything more powerful/larger.

Worked out that my joists are around 1.5 x 3.5s, so pretty damn awful. Got 2x5s sistered in with some help and it’s gone from not great to walk on to being rock solid.

Need to get all the insulation back in and then I’ll look at a raised floor over the insulation.

Once that’s done it should be solid enough to set up and heat test.

Also, traced where the power cables go down to the consumer unit so that I can put in some new circuits for this.

Definitely coming along slowly but surely.
Click to expand...
Strongly recommend a licensed electrician for ANY electrical work you add on. Don’t know how new you are but another RIU member experienced a fire near Christmas in an attic grow from unsafe electrical setup. Also suggest a waterproof basin for plants to sit in.
 
coreywebster

coreywebster

Well-Known Member
Get your water plumbed in and a small drain plumbed in up in the attic if you can.
It will save you a lot of effort further down the road.

Use a proper roof flue for extracting the heat.
There shouldn't be a heat sig for a chopper to see if your in a tent and vent out of the house, but an air brick with heat sig will stand out to a chopper where a roof flue wont. That should be the only heat sig visible by flir.

Rigid insulation between roof joists will help greatly. Keeping the air exchanging should make it a fully usable space.

Sounds like a great space to work with if you do everything right.
 
S

SmokinTheHerb

Active Member
S

SmokinTheHerb

Active Member
hotrodharley said:
Strongly recommend a licensed electrician for ANY electrical work you add on. Don’t know how new you are but another RIU member experienced a fire near Christmas in an attic grow from unsafe electrical setup. Also suggest a waterproof basin for plants to sit in.
Click to expand...
Thanks for the advice, this part however I’m definitely capable of doing.

I’ve studied the basics, got all the testing tools needed to do an electrical installation report same as a sparky would. Got my on site guide to confirm acceptable results.

So I’m happy enough running up some serious cable and putting in a consumer unit up there with individual appropriately rated breakers for the loads I’ll see on each circuit.

But that’s a way off anyway, need to get the building and insulation works all sorted before I even look at power.
 
Rainbow Warrior

Rainbow Warrior

Well-Known Member
SmokinTheHerb said:
This looks good mate.

Don’t know anyone to fit it but I’ve got excuses for needing to get hot air out of the place so should be able to call in a pro and justify it.

I’ll ask around mates first tho.
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Just offer one of your mates 1/2 ounce of ur first crop to fit it for u; if it all goes tits up and you get no yield for whatever reason, then u don’t owe him anything.
 
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