Hallelujah! The Building Permit has arrived ... just in time for next season!

After five months (less a week) of submissions and questions and re-submissions we now have our Building Permit from the City of Toronto.

 

Five months seems along time to get a permit for our rather modest undertaking, all things considered.  It's not as if we are building a whole house or building a swimming pool

Part of the dilemma is that the City staff who work on residential scale projects have very little experience evaluating green roofs, and tend to "throw the book " of regulations at it.  At various times I spoke with four different layers in the system, and while they are all very positive and helpful, only the manager seemed to truly understand what was going on.

They might have green roofs for condominiums well under control, but they do need more staff training on residential scale undertakings, if only to save time in the permitting process.

Part of the dilemma was that I did not understand the minute details needed on one key element, until very late in the process.

Key points going forward....

• Make sure your roof is designed for the load 2 - 3  kPa (40 - 60 psf) - depending on your planting aspirations - right from the get go.  254mm - 305mm joists at 406mm or 300mm centres.  The smaller sized 150mm or 200mm timber is just not strong enough, especially at the wider spacing.

• Be realistic about your horticultural aspirations, as the the depth of your growing medium is the limiting weight component when wetted.
  
  Sedums vs wild flowers and grasses vs a vegetable garden vs shrubs vs trees?
  
  1,200 kg/m3 is a good place to start for a light weight growing medium at "field capacity".

• Green roofs is "dead load" and you also need to include the self load of the roof, along with the snow load.

• Wind uplift is a key concern at City Hall - they don't want your installation blowing away and nor do you.  This was a very time consuming matter!
  
  I could not find a strictly Canadian solution for the complete calculations.
  
  You will need to use NBC 2010 (or better)  for the raw wind pressure information - q(1/50) and composite pressure - gust coefficients, etc
  
  It appears that the German uplift calculations, as documented in the engineering report prepared by Strodthoff & Behrens GmbH; “Assessment of positional security against wind uplift for a roof planting system that is permeable to wind”, report No. 1/21010/10.99 dated Nov. 25, 2009", are acceptable when an independent (engineering) consultant provides site specific results for your installation.
  
  Examples of these calculations can be found in a number of web sites, including the XeroFlor sites : www.xeroflor.com and www.xeroflorcanada.ca
  
  I am willing to pass on my Toronto contacts via off-line communication.

• Professional engineers who stamp the drawings for their own home are not immune from additional independent 3rd party analysis and reporting requirements.  My drawings had  three different stamps on parts of them, not counting the structural engineer from the original house.  Professional engineers stamps cost money and take time!

Part of our dilemma is that a building permit issued on 01 October is not useful in the current 2014 growing season.  The lead times for some of the required input "product" would put the installation into late November or even December.  

So we have flagged it for May in 2015 and will be stepping forward vigourously at that time.

Words to the  wise - If you want a (Toronto) Building Permit ready to go in May then get started in October the year before.

On ward and upward!

The Building Permit Application #3

Applying for the Royal Building Permit.

Quite a bit of water has been flowing under the proverbial bridge since April.  So far I have put in three increasingly complex building permit (BP) applications, not counting the inaugural informal discussions. Each time,  I received slightly better but slightly different information from staff, and it took a good session with the manager of the examiners to (I hope, finally) determine what is acceptable.

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.