Fire Wall Does Not Extend to Roof in Row Townhouse

[sunyaer]

The first image is a row townhouse under construction, the second picture is from Ontario Building code. The attic of the first picture looks like inaccessible, and the fire wall does not extend all the way to the roof as required by Ontario Building code based on the second picture.

Is this row townhouse being constructed compliant with Ontario Building Code?

 

[ICE]

The construction appears to be incomplete so your assessment might be premature.

 

[Genduct]

Townhouse OR Multi-Family?

 

[sunyaer]

Townhouse OR Multi-Family?

I would think it's townhouse.

 

[e hilton]

Can they add a sheetrock fire wall on top of the blocks? I’m thinking it was easier for the mason to build a flat top wall, and the gc has another solution.

 

[Genduct]

I would think it's townhouse.

I find it hard to believe the Plan Review missed a required Rated Assembly

 

[steveray]

I am assuming they are just building it wrong...typical....They might figure out how to patch the top....

 

[TheCommish]

Maybe the masons coming back to block to the underside of the roof, easier for them to match the pitch after.

 

[SCBO1]

Does Candian building code allow for walls to covered with fireX drywall to be placed above the block fire wall and also be placed on the underside to the roof rafter?

 

[Plumb-bob]

Firewall is a defined term that functionally subdivides a building into 2 smaller buildings. What you are showing is a vertical fire separation with a fire resistance rating. This fire separation shall either terminate at the roof deck or at a horizontal fire separation of the same rating.

 

[tmurray]

Plumb-bob is correct. What is being shown here are fire separations. The fire separation needs to either continue vertically to the underside of roof deck, or can be carried across the ceiling of each fire compartment. As suggested by others, it is just the rating of the separation that needs to be consistent, not the materials. They could easily construct a wood and gypsum assembly in the attic.

The advantages to concrete are increased sound dissipation with the denser materials.

There would be no advantage to constructing firewalls in this instance.

 

[Inspector Gadget]

The first image is a row townhouse under construction, the second picture is from Ontario Building code. The attic of the first picture looks like inaccessible, and the fire wall does not extend all the way to the roof as required by Ontario Building code based on the second picture.

Is this row townhouse being constructed compliant with Ontario Building Code?

Insufficient information. The concrete block may would only need to be a firewall *if* it is being used in construction where
a) the wall also sits on a property line, that is, each unit has its own owner, PID, title, etc;
or
b) the firewall is dividing the structure into two separate portions so that each portion can be treated as an individual building - usually used to escape more onerous construction provisions (non-combustible versus combustible, sprinklers, etc.).

The other replies given to you, therefore, are quite valid.

Can they add a sheetrock fire wall on top of the blocks? I’m thinking it was easier for the mason to build a flat top wall, and the gc has another solution.

Does Candian building code allow for walls to covered with fireX drywall to be placed above the block fire wall and also be placed on the underside to the roof rafter?

Presuming this is a part 9 building, the answer to both is "yes."

9.10.11.2. Firewalls Not Required
1) Except as stated in Sentence (2), a party wall on a property line of a building of residential occupancy need not be constructed as a firewall, provided it is constructed as a fire separation having not less than a 1 h fire-resistance rating, where the party wall separates
a) two dwelling units where there is no dwelling unit above another dwelling unit,
b) a dwelling unit and a house with a secondary suite including their common spaces, or
c) two houses with a secondary suite including their common spaces.
2) Where a building of residential occupancy contains more than 2 houses, a party wall that separates any 2 adjacent houses with a secondary suite from the rest of the building shall be constructed as a firewall to create separate buildings each containing no more than 2 adjacent houses with a secondary suite.
3) The wall described in Sentence (1) shall provide continuous protection from the top of the footings to the underside of the roof deck.

 

[Plumb-bob]

That building is either Pt3 by size, or very close to it.

If those are firewalls they will need to extend past the roof to form parapets, and be designed with sufficient structural integrity to survive under fire conditions.

If they are party wall fire separations, they need to terminate at the roof deck as stated in 9.10.11.2 (3).

The more I look at the pictures the more curious I get.

 

[tmurray]

Insufficient information. The concrete block may would only need to be a firewall *if* it is being used in construction where
a) the wall also sits on a property line, that is, each unit has its own owner, PID, title, etc;

Typically just a party wall would be used in row housing like this. The secondary suite thing is where this has a tendency to get sticky. You can only have two dwellings with secondary suites, so if you have 6 units in the row house, how do you designate which two are allowed to have secondary suites? Some jurisdictions are requiring firewalls to break the building into buildings of 2 townhouses each. Others are simply not permitting secondary suites in row housing at all.

 

[sunyaer]

Update on the original post. They did insert dry wall between trusses on each side of the CMU wall. The top course of CMU is a bit wider which are supporting the truss.

Does the fire separation made of wood strips with dry wall on both sides meet the fire resistance rating which is 1 hour?

 

[tmurray]

The short answer is that it is unlikely. Assuming this is Part 9, there are three options for fire resistance ratings:

Table A-9.10
CAN/ULC-S101
Appendix D

Table 9.10 has assemblies that are calculated based on a bunch of fire rating testing. The assembly would have to be listed in the tables to be valid, but there is nothing in the table for a truss clad in gypsum.

CAN/ULC-S101 is the only real option. Systems must be constructed full-scale and undergo fire testing in a laboratory. It is conceivable that there has been some of these assemblies tested, but I have not seen them.

Appendix D is the most flexible option for fire resistance ratings for wood frame construction using the component additive method. The issue in this case is that a truss is not one of the components that you can use.

The building official could use their discretion to permit this construction. We do not allow it over concerns of the performance of the truss connector plates when exposed to heat and the differential expansion between the wood and metal. More recently, this position was adopted by the New Brunswick Fire Marshal Office, removing it as an option throughout our province.

You are wise to question it's performance.

 

[Inspector Gadget]

Update on the original post. They did insert dry wall between trusses on each side of the CMU wall. The top course of CMU is a bit wider which are supporting the truss.

Does the fire separation made of wood strips with dry wall on both sides meet the fire resistance rating which is 1 hour?

Highly unlikely... unless there are two layers of drywall. Tmurray pretty much said all that was required, but I'm going to add my two nickels.

• In my experience, you're not able to achieve 1 hour without 5/8 Type X, resilient channels and insulation.
• NBC 2015 has introduced a bit of a challenge with using Appendix D: Table D 2.34.-A will NOT allow 5/8 Type X to give a rating if used on a non-loadbearing wall constructed of wood.
• Further if this is a part 3 building, the only pathways are Appendix D or ULC-listed assemblies.
• And any walls demising residential suites must have an STC of 50.

Bottom line: this all ought to have been solved at the plans review stage.