Hoisting the GM

Hoisting the Growing Medium (GM)

Following the installation of the edge railing, the next layer to be installed was the drainage layer. It was the same highly porous open weave material as was use don the kitchen roof.  It cuts with scissors and is laid with the grey filter fabric side facing up.

The next layer was a double layer of the water storage cloth.  While the open areas are pretty straight forward, the multitudinous corners took a lot of dovetailing and other finessing to ensure that there were no pathways for the GM to sluice through.

Wide spaces are quick and easy : two layers set perpendicular to each other.

Corners take a lot more finessing to ensure double coverage.

Corners are quite time consuming and fiddly.

And then the BIG DAY comes ... to hoist the growing medium.

It's a big day because this was the first of only two tasks that I could not do myself.  I needed heavy machinery and operators.  The GM was delivered in 1 cubic yard totes, each weighing about a ton.  In hindsight we were lucky to not be using the SOPREMA GM which is delivered in 4 yard totes - destined for large areas like condo and factory roof tops.

Growing Medium is NOT soil.!! No one says what is really in GM, but Xeroflor describe it as a proprietary mixture of lightweight, mineral based materials; including porous aggregate and organic matter derived from composted plant materials.  It is more mineral than organic, so it won't break down and disappear to quickly like soil would.  Our GM had a noticeable red hue to it from crushed brick material.

The sizing of the GM was in the grit to fine gravel range. All sub- 3/8".  Very little in the clay-silt-fine sand sizings.  Not all all well sorted.

Here is a post -hoist photo of rain-washed growing medium.  It has a distinctly red hue from the crushed brick component.

In our installation we planned to use a 4" (100 mm) layer on the main roof, amongst the solar panels, with a 6" (150 mm) layer of GM being used on the roof of the 3rd storey walkout.  

Why 1 ?? Because that's all we could reasonably hold within the structural limitations of the roofs.

Why 2?? Because a thickness of GM would provide additional water storage to reduce the frequency of watering.

Why 3?? Because we might elect to broadcast some native plant seed next spring, and they grow better (more reliably) with some GM into which they can stretch their roots.

Then the issue is how to move about 6 cubic yards of this stuff up 25 (8 m) or 35 ft (11.5 m).  My back was not that strong.  However Lino's loader was. 

Our neighbours were building a home and friend Lino,  the framer, had a "zoom boom" that was rated for 1 ton up 42 feet.

Lino's "zoom boom" without which we would have been skunked, and substantially poorer.

Lino is always good for a challenge, and came over in the evenings to help out.. We put totes destined for the highest roof 35 ft (11.1 m) onto a pallet and then hoisted it over the edge of the roof.  The totes for the main roof, at its lower elevation of (only) 25 fee,t were hoisted by their own straps.

The active end of Lino's loader, from the top, down about 30 feet..

I then cut away the side or bottom of the tote so its contents fell gently into a temporary hopper.  From there we shoveled it out around the roof with snow shovels, raking it into place but not compacting it particularly.

GM spilling gently onto the 3rd storey walkout roof.

Temporary hopper that holds about a yard of GM . We then shovelled it around the roof with grain / snow shovels

Getting started.

Vital tools

This funny looking jut-out is to provide space for the adjacent electrical control box to be opened.  It has the circuit breakers for the individual chains of solar panels and might be needed for SP maintenance: assuming you can still open it.

.

Almost there.

Finished, ready for the living layer.
The GM is finished off about an inch below the top of the edging, by design.

Raked, but not compacted.

What does hoisting cost?.  Depends!.  Buddy rates are negotiable.

Commercial rates for a crane truck that could lift 1 ton about 40 feet "up" and 10 feet traversely ("over") run about $165 per hour (Ontario, 2014) : four hour minimum, including all travel time.

Our dilemma was that we could not hoist all 6 yards in the same session as we did not have places to temporarily stage them within reach of a regular crane truck. In the end we did it in 3 separate sessions based on 3 different staging areas.

 A substantially bigger machine would have been needed to increase the dimension of the traverse distance covered.   We needed to hoist 1 ton  30 feet horizontally at 40 feet vertically.  A bit of a challenge $$$$$$!

Friend Lino and his marvellous lifter fitted the bill wonderfully.

Preparing the Kitchen Roof - Layers Upon Layers

Preparing the Kitchen Roof - Layers Upon Layers

A little water has flowed under the bridge of time, and now I must finish the documentation. I left the kitchen roof at the rivets and railings stage.  

Day 3

Finished off the railings on the kitchen roof today. It transpires that it is easier to terminate or join the railing segments mid-span rather than in the corners. Mainly because its easier to assemble up on the roof with much less drilling, screwing and riveting. The Xeroflor railing system come with a neat little u-shaped brackets that you and use with self-tapping screws to make joins very quickly on straight pieces. These joiners don't work in corners and you then have to connive a stable connection. Which takes time. Inordinately...

The next layer is .......

Layer 4  - Drainage Layer

This is a coarse looped material known as XF 108H at Xeroflor.  The XF 108H drain mat is a three-dimensional, lightweight, and flexible composite material made up of a drainage core of looped polyamide filaments bonded to a specially perforated, nonwoven filter fabric, to quote from the product doc.  Its quite stiff but has "bounce back body". It crushes when you stand on it but then sprigs back to an open 3/4 inch thickness.

I put one layer everywhere inside the railing, and  a second layer along the downstream edge to provide a drainage pathway underneath the railing.



This stuff comes in 60 m long rolls and is quite light.  One person can carry a whole roll.  Cuts with regular scissors.  It lays down quickly. The black loopy side goes "down" with the fabric filter cloth on the "up" side.

Here is the drainage layer installed across the kitchen roof.

The next layer is .....

Layer 5: Water Storage

On of the problems with roof gardens is moisture - as in insufficient.  So we put in "growing medium" (in lieu of soil) which can hold some moisture, and fleecy felted layers of "water storage.  Otherwise we would be watering almost continuously in the bright sunny and very hot roof-top environments. 

We used a thick fleecy material called "XF157  Water Retention and Filtre Fleece.  It is about 1/4 inch thick and comes in 20 m by 1.3 m rolls and can be cut with kitchen scissors.

It looks like recycled cotton / felt.

I ended up putting two layers on, with seams at 90 degrees to cut down the risk of growing medium flowing ( or is it subsiding) away.   I spent some time dovetailing the corners of the fleece to ensure that all the growing medium (next layer) is retained up on the roof. 

The timber is just to hold the fleece down "overnight" in the absence of the next two layers.

End of Day 3. Now we need to find some sedums and growing medium.

Spring Has Sprung, Finally......

Spring Has Sprung! 

(last week for a few days, maybe....)

Spring has sprung, the grass is riz, I wonder where dem boidies iz?

After a long and quiet winter staring at my Building Permit I have finally ordered some stuff and we are moving ahead yet again.  My driveway and garage now resemble Home Depot on a bad day.

The delivery #1 was on a rainy day so the absorbent layers were stuffed into the garage.  The family car is "out" for the duration.

Growing medium does not look particularly light-weight at all.

 The "drainage layer is actually very light so won't be too big a deal to install it.

This afternoon we start the serious work on the railing and root barrier for the kitchen roof.  It is the most accessible - "most" being a relative term.  

We're now on a bit of a timeline as the sedum mats are arriving on the Friday of the May long weekend - only 3 weeks away. 

I did have a (n e-mail) chat with my local City building inspector to learn that they will be delighted to look at it  - when its finished.

Full steam ahead and dodge the torpedoes!

Will keep you posted.

BTW, I had the pleasure of helping out at Don Mills CI on their Earth Day celebration this week  Spoke to some slides for half an hour about Cool Roofs : PV Solar Systems and Green Roofs. It went well and they were a very receptive audience. About 250 teenagers and a few staff.