"False Ceiling"?

[E87]

I have a project where the structural engineer is proposing to frame over an existing roof with a new roof but leave the existing roof in place. Would this be considered a "false ceiling"? Is there anything in the building code dealing with something like this? I mean, is this ok to do? I have never come across something like this situation and I just want to make sure it is ok before i give the engineer the ok to proceed. The existing roof is in good condition structurally, no worry of colapse or anything like that.

Any comments are greatly appreciated! Thanks!!

 

[mark handler]

Not a false ceiling, a false ceiling is commonly refered to as a dropped ceiling But there is really no such thing as a "false ceiling" It is or is not the ceiling

And yes it is Okay in most cases to leave the old framing. Its similar to so called california framing, framing over framing.

 

[brudgers]

1. require a structural engineer to verify that the existing roof structure is capable of supporting the additional dead load and that the MWFRS is capable of handling any additional lateral loads or uplift, likewise for seismic.

2. make sure that access is provided to the new attic.

3. make sure that sufficient attic ventilation is provided to allow the failed roof to dry out over time.

 

[fatboy]

crap.........I hate when I have to agree with brudgers........although i would add, access to new "attic" required only if space exceeds 30" free space between top of "ceiling joists" and bottom of new rafters.

 

[cda]

Hard on firefighters when it burns

 

[fatboy]

yeah, but allowed...........

 

[Mark K]

If the new roof is self supporting the existing roof need not support any additional loads.

What the engineer will have to do will be dependent on whether the whole building needs to be brought into compliance with the current code and what if anything is to be done to the existing lateral system.

 

[Francis Vineyard]

What is the construction type; fire classification of the roof covering; is it NFPA 13 and will draftstopping in attic be required?

Check height Table 503.

 

[steveray]

Concealed combustibles?....Is the old roofing allowed to be "inside" the building?...Just a couple that come to mind...

 

[TimNY]

I am envisioning a draftstopping issue.

From a firefighter point of view I am cringing. Luckily training for these taxpayer reroof debacles is widespread.

 

[Frank]

Is specifically permitted see IBC 1510.3 exception 1

 

[Francis Vineyard]

Is specifically permitted see IBC 1510.3 exception 1

Frank

Are you saying that section permit exceptions of other chapters as previously mentioned or just confirming that a new roof can be built over the old?

 

[permitguy]

As others have said, make sure the FD knows about it. If they preplan, they'll probably want to add a note. Similar instances have caused FF fatalities.

 

[SCBO1]

Does it need an attic stairway?

pc1

 

[brudgers]

Hard on firefighters when it burns

That's an image I didn't need.

 

[Frank]

Permits new roof over old.

Draftstopping still required for the concealed spaces.

Attic access still required if over 30 inch clear height.

If sprinklered, NFPA 13 combustible conceled space rules would apply.

 

[Alias]

Agree with brudgers. I have an old service station with metal walls and framing and they want to put another roof over the entire existing building. I told them that I needed engineered plans before they could proceed.

 

[Examiner]

Yep, new roof over old has been addressed in several previous post. I had one last year.