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Ontario Building Code question on depth of footing

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  • Jul 21st, 2009 8:26 pm
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Deal Addict
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Apr 26, 2001
2697 posts
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Ontario Building Code question on depth of footing

Just ran into an issue with the township building code requiring 60" below grade footing or pier with a base for a deck with an aluminum and polymer sunroom on it.

Also require 6" x 6" posts for support to the cement column.

The local town hasn't adopted these ontario wide 2006 rules so wonder why they're so stringent and overkill for our local frost level of 18".

My old deck was on cement surface pads.

Any opinions?
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Deal Addict
Dec 26, 2005
2796 posts
21 upvotes
Mississauga, ON
blackhawk wrote:
Jul 20th, 2009 6:46 pm
Just ran into an issue with the township building code requiring 60" below grade footing or pier with a base for a deck with an aluminum and polymer sunroom on it.

Also require 6" x 6" posts for support to the cement column.

The local town hasn't adopted these ontario wide 2006 rules so wonder why they're so stringent and overkill for our local frost level of 18".

My old deck was on cement surface pads.

Any opinions?
Poor soil conditions?
You are replacing a deck that may never have had a permit. Now putting in a structure with both people load and winter snow load.
Jr. Member
Feb 28, 2007
119 posts
Ottawa
There could be lots of reasons why they require 5'-0" cover. I personally would rather put couple of cubic feet extra concrete (i.e difference between 18" and 60") rather than deal with the foundation problems that occur during soil frost heave action.

I don't quite understand "Also require 6" x 6" posts for support to the cement column. " Usually 6"x6" posts sit on a circular concrete column/foundation (also called sonotube) not the other way around. Please clarify.

Any questions feel free to ask.

Thanks.
blackhawk wrote:
Jul 20th, 2009 6:46 pm
Just ran into an issue with the township building code requiring 60" below grade footing or pier with a base for a deck with an aluminum and polymer sunroom on it.

Also require 6" x 6" posts for support to the cement column.

The local town hasn't adopted these ontario wide 2006 rules so wonder why they're so stringent and overkill for our local frost level of 18".

My old deck was on cement surface pads.

Any opinions?
[OP]
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Apr 26, 2001
2697 posts
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the cement 10" column is from 60" below grade to the surface with the 6 x 6 from the cement pier to the deck beam where the joists will rest

as for soil conditions, the 60" rule is across ontario as its in the basic code so I'm assuming its simply a structural requirement that encompasses frost levels from windsor to winisk
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Jr. Member
Feb 28, 2007
119 posts
Ottawa
Hi there,

Now its much clrearer. Take a look at this website it has some details that maybe useful: http://www.elginconnects.ca/portal/uplo ... s/6092.pdf

Yes 60" rule is across Ontario. Normally if its a big project you would hire geotechnical engineer, who will do some testing and specify what depth of frost cover you need. For example, if you are resting your footing on rock, usually you don't need any frost cover because most rocks are not frost susceptible. However, residential projects are considered Part 9 of Building Code, and therefore requirements for them are based on a rule of thumb (i.e. experience gathered over years) rather than scientific aproach.


blackhawk wrote:
Jul 21st, 2009 6:10 am
the cement 10" column is from 60" below grade to the surface with the 6 x 6 from the cement pier to the deck beam where the joists will rest

as for soil conditions, the 60" rule is across ontario as its in the basic code so I'm assuming its simply a structural requirement that encompasses frost levels from windsor to winisk
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