Applying for the Royal Building Permit.
The staff of the Building Department do not see too many BP applications for green roofs for SFD, and certainly not ones submitted by home owners. The desk staff are very helpful, but you need to appreciate that your application is far from their run-of-the-mill work load.
So, the key points that were needed before the City would accept my application are shown below. YMMV!
- Know how strong your roof is.
- Know your units : 1kPa = about 21 psf (20.885434273). 2 kPa of snow or green roof weighs about 42 psf and that is fairly heavy.
- A layer of light-weight growing medium 25mm / 1" thick is calculated to be 0.3 kPa, just over 6 psf - at "field capacity for moisture".
- Your growing medium loads will all be calculated at field capacity to allow for the moisture that is stored within the soil matrix. It is the water left behind when the drainage layer has removed all naturally / gravitationally available storm or irrigation water.
- This is sometimes called the "wet density". About 1,200 Kg per cubic metre, approx, but does vary quite a bit by vendor.
- [Don't use soil / triple mix - way too heavy unless your roof is very substantial. ]
- Roof structural loadings is but a numbers game when push comes to shove.
- The City of Toronto treats green roofs as "dead load". This will affect your calculations of loadings.
- Live load is when you walk on the roof to maintain the vegetation.
- Become well versed about "wind uplift". There are several documents and resources on the www, but most of them are based on one study from WSP Engineering on Nov 25, 1999 and commissioned by Strodthoff & Behrens GmbH. I understand this report was paid for by XEROFLOR, and parts of it are available from their website. Thank you XEROFLOR for making it publicly available.
- NRC Canada can provide some local wind uplift data.
- Ensure that all specifications and drawings are stamped by a professional engineer. Whether it is your hired engineers stamp or your own (engineers) stamp seems to make no difference.
- Home owners (in Toronto) can stamp their own designs, calculations and drawings so long as your are an Ontario P.Eng with a "stamp". I think there might also be a limitation if you sell the home within a short period of time.
- It's a poor pun, but to paraphrase the Ontario Gaming Commission - "Know Your Limits : Play Within Them". Applies to home owner / engineer / designers, as well.
- If using hired design or engineering staff, they should have a BCIN (Building Code Identification Number) - signifying that the Province thinks the person, or their corporation, knows the Ontario Building Code "sufficiently".
- Put all your design information onto drawings - the City staff don't seem to like scoping reports or letters, unless they request them.
- Get all the drawings and specification documents stamped
- It is really, really handy to have quick access to a scanner so you can sign / scan / submit documents and forms. Most of the forms are legal sized (8.5" by 14") paper.
- There are three obligatory City Forms to be filled.
- Forestry (even if you don't touch any trees - its a sign-off),
- Designer Information,
- BP Application Form
- plus the Consultant Form if you use consultants / designers / engineers
- You will also need to submit a Green Roof Declaration and keep any eye out for Section 4-iii wherein you or your designer needs to substantiate any part of the installation that has growing medium thinner than 100 mm (4").
- Develop a Maintenance Plan as part of your submission.
- Submit all the application documents electronically on a DVD-RW. No other digital format is acceptable, although I think might be able do it on-line. I did it in-person because they are close to home, and I usually learn a lot through the chit-chat with staff.
- Merge all the "documents" into one pdf format file.
- Merge all your "drawings" into one pdf format file
- Keep the City forms as separate pdf's - they get sent in different directions.
- If using old drawings, they need to be cleaned of all forms of prior approvals or notations. Leave the engineers stamp, but remove everything else.
- All documents and drawings, etc, to be published in black and white - no colour.
- Leave your paper at home. They will send it home anyway! They even send you away with your DVD-RW in your pocket.
The BP application is treated as a "Re- Roofing" and the fee is calculated at $5.36 per sq m, (June 2014).
The BP Application turn-around is said to be in the 6-8 week range.
That gives me plenty of time to apply for the Toronto ECO-Roof Incentive Program Grant. All things going well, the City will provide a grant of $75 per sq m which will help my cash flow substantially. There is some fine print. Read it at their web site.
So now we wait patiently, calculating quantities, getting quotations from vendors etc, watching the soccer ... patiently staring at my grubby D50 membrane.
