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spaceboy 02-25-2013 11:34 AM

Attic Ceiling Joist Install Question
 
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Finally getting around to turning my attic into livable space. House was built in 1903 - cant understand how its made it this long without anyone taking this project on.

The support in the photo (Pardon the messy workspace - i really need to get up there an clean up a bit!) is an old piece of floor plank and offers no structural support - I have removed about 10 of these throughout the attic so far.

My plan is to install 2X6X10's or 8's (didnt measure yet to see exactly what size i need) about 2 feet above the top of the skylights

My question is - when attaching these to the roof framing - should these be nailed or bolted?

These will be used as a ceiling joist and depending how much room I have up there - I may throw some some plywood over it and use it for storage space.

joecaption 02-25-2013 11:45 AM

#1 Please go back and add your location to your profile, yes it makes a big differance on this one.
When you see what's going to be involed in this you may see why it was not done before.
What's the width, spacing, and free spans of the floor joist. Most attic were not build for a living space. Under sized floor joist will cause damage to the ceiling below.
Your going to need a permit for this.
I hope your not talking about the cross ties when you said you removed them.
There to keep the roof from spreading and keep the ridge beam from sagging.
May have to shim out those rafters you have now and add a ridge vent in order to fit the needed insulation.
http://www.energystar.gov/index.cfm?...sulation_table

Your also going to need a real stairway that's to code.
How do you plan on heating and cooling?

GBrackins 02-25-2013 11:56 AM

hard to tell from your photos so I have a few questions:

do your rafters:

1. sit on top of the attic floor?
2. do they sit on top of a wall below the attic floor?
3. do they sit on top of a short knee wall above the attic floor?

spaceboy 02-25-2013 12:02 PM

Quote:

Originally Posted by GBrackins (Post 1124542)
hard to tell from your photos so I have a few questions:

do your rafters:

1. sit on top of the attic floor?
2. do they sit on top of a wall below the attic floor?
3. do they sit on top of a short knee wall above the attic floor?


They sit on-top of a short knee wall above the attic floor. I intend to build additional knee-walls to help with support.

spaceboy 02-25-2013 12:06 PM

Quote:

Originally Posted by joecaption (Post 1124530)
#1 Please go back and add your location to your profile, yes it makes a big differance on this one.
When you see what's going to be involed in this you may see why it was not done before.
What's the width, spacing, and free spans of the floor joist. Most attic were not build for a living space. Under sized floor joist will cause damage to the ceiling below.
Your going to need a permit for this.
I hope your not talking about the cross ties when you said you removed them.
There to keep the roof from spreading and keep the ridge beam from sagging.
May have to shim out those rafters you have now and add a ridge vent in order to fit the needed insulation.
http://www.energystar.gov/index.cfm?...sulation_table

Your also going to need a real stairway that's to code.
How do you plan on heating and cooling?

The floor-joints are currently spaced 2x6's spaced 16" apart. The 2x6 run about 12' to a main load bearing structural support that runs directly through the middle of the house. Total width of the house is 24'. From what I have read on structural loads - 2X6 is good to a 12' span.

The cross ties could not have been doing anything that the new 2X6's cant replicate. Not to mention - I doubt they were actually doing anything just based on how flimsy the wood was. From my research - the floor joists are my rafter ties based on the way the home was built.

As for the insulation - here is the plan:
Rip pieces of 1.5 rigid foam to fit between the existing rafters
- Double up the foam in every 4-5 rafters then every 6th rafter – only use 1 piece and Keep the foam flush with the lower edge leaving an airspace @ the roof sheathing for venting.
- Next, apply full sheets of foam to the outside & install furring strips for drywall.
I’m in Chicago and this will get me to an r value of 22.5 for the walls and then I will use r13 fiberglass between the ceiling joist and then blow/roll R 30 above that.

spaceboy 02-25-2013 12:45 PM

Sorry - I kinda peiced those answers together.

Let me know if you have any other quetsions and thanks in advance for your help on his questions - its great to have experts to turn to for guidance!

GBrackins 02-25-2013 01:17 PM

Quote:

Originally Posted by spaceboy (Post 1124555)
From my research - the floor joists are my rafter ties based on the way the home was built.

if you have balloon framed construction then the floor joists do help with resisting rafter thrust, and sort of act as rafter ties.

if the knee wall is built on top of the attic floor then you need either rafter ties located in the lower 1/3 of the height from top of knee wall to ridge or a structural ridge beam.

Collar ties located in the upper 1/3 of the height from top of knee wall to ridge resist uplift on the leeward side of the roof and prevents rafters from pulling out of the ridge.

is you wall balloon framed (continuous from foundation to top of wall) or is it platformed framed?

spaceboy 02-25-2013 01:19 PM

Quote:

Originally Posted by GBrackins (Post 1124631)
if you have balloon framed construction then the floor joists do help with resisting rafter thrust, and sort of act as rafter ties.

if the knee wall is built on top of the attic floor then you need either rafter ties located in the lower 1/3 of the height from top of knee wall to ridge or a structural ridge beam.

Collar ties located in the upper 1/3 of the height from top of knee wall to ridge resist uplift on the leeward side of the roof and prevents rafters from pulling out of the ridge.

is you wall balloon framed (continuous from foundation to top of wall) or is it platformed framed?

The wall is balloon framed as it is continuous from the foundation to the top of the knee wall.

kaschmid3 02-26-2013 06:55 AM

Do u have 20 ft studs how old Is house balloon framing hasn't been done in about 100 yrs

kaschmid3 02-26-2013 06:57 AM

If it is ballon framed I would solid block every bay sy bottom( since balloon frame had no bottom plates) this would be for fire code

joecaption 02-26-2013 07:05 AM

With ballon walls you can drop something all the way from the attic to the crawl space.
That area acts like a chimmney in a fire and allows critters free access to the inside of the walls.
Fire blocking needs to be done.
http://sfsafetraining.com/BalloonFraming.pdf

GBrackins 02-26-2013 08:29 AM

2x6 are sufficient for a 10' span with a 20 psf live load. attach them to the sides of parallel rafters with (5)16d common nails per the American Wood Council's "Wood Frame Construction Manual." If you are planning on placing plywood on top and using the space as storage you may need to increase to 2x10 or 2x12 for proper insulation unless you are planning on creating a conditioned attic space.

Your existing attic is currently not living/conditioned space. Typically when changing this type space into living space you must comply with the current building code.

A few items to verify with your building department as to whether there are required by your local building code:

-insulation requirements, which determines assembly thickness based upon type of insulation
-if space is used as bedroom(s) you will need to provide an Emergency Escape and Rescue Opening (minimum 1 per bedroom) verify size of clear opening with building department.
-verify if the bottom of windows must be at least 24" above the finish floor due to code requirements since the bottom of the window is more than 6' above the exterior grade. Windows typically less than 24" above the finish floor and more than 6' above the adjacent grade are required to have a device that limits the opening of the windows to no more than 4" without releasing the device. This is to prevent children from falling out of windows. Emergency Escape and Rescue Openings (bedrooms require at least 1 typically) are not allowed to use these devices since they require special knowledge
-if space is used as bedroom(s) you may need to install hard-wired smoke detectors through out your home
-access stairs unless existing will need to meet the requirements of your building code

Sounds like you have found an excellent way of providing more living space to your home. Post back with any questions.

Good luck!

spaceboy 02-26-2013 12:15 PM

Quote:

Originally Posted by kaschmid3 (Post 1125171)
Do u have 20 ft studs how old Is house balloon framing hasn't been done in about 100 yrs


the house was built in 1903.

Thanks for all the assistance on this. I have a structural engineer coming over this afternoon just to take a look at it/put me at ease.

spaceboy 02-26-2013 12:20 PM

Quote:

Originally Posted by GBrackins (Post 1125211)
2x6 are sufficient for a 10' span with a 20 psf live load. attach them to the sides of parallel rafters with (5)16d common nails per the American Wood Council's "Wood Frame Construction Manual." If you are planning on placing plywood on top and using the space as storage you may need to increase to 2x10 or 2x12 for proper insulation unless you are planning on creating a conditioned attic space.

Your existing attic is currently not living/conditioned space. Typically when changing this type space into living space you must comply with the current building code.

A few items to verify with your building department as to whether there are required by your local building code:

-insulation requirements, which determines assembly thickness based upon type of insulation
-if space is used as bedroom(s) you will need to provide an Emergency Escape and Rescue Opening (minimum 1 per bedroom) verify size of clear opening with building department.
-verify if the bottom of windows must be at least 24" above the finish floor due to code requirements since the bottom of the window is more than 6' above the exterior grade. Windows typically less than 24" above the finish floor and more than 6' above the adjacent grade are required to have a device that limits the opening of the windows to no more than 4" without releasing the device. This is to prevent children from falling out of windows. Emergency Escape and Rescue Openings (bedrooms require at least 1 typically) are not allowed to use these devices since they require special knowledge
-if space is used as bedroom(s) you may need to install hard-wired smoke detectors through out your home
-access stairs unless existing will need to meet the requirements of your building code

Sounds like you have found an excellent way of providing more living space to your home. Post back with any questions.

Good luck!


Thanks Gary...

The floorplan is all dictated based on window access to stay within code.

Both beds will have 2 windows and the bath will have one. Skylights also vent/open but i doubt that is up-to-code to be considered a window.

Have an structural engineer coming over today - just to take a look at current 2X6 in the floor. He claims based on what i described - I should be ok but I want to be safe and sure that everything i put up there... stays up there!

GBrackins 02-26-2013 12:59 PM

sounds like you have a good plan of attack ...... keep us posted please


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