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-   -   Sister joist, replace wood bean, what wood grain? (http://www.diychatroom.com/f19/sister-joist-replace-wood-bean-what-wood-grain-68811/)

jpcada 04-11-2010 01:19 PM

Sister joist, replace wood bean, what wood grain?
 
5 Attachment(s)
I was replacing the hardwood floors of the 1st floor (basement for DOB) in my brownstone and I found that some of my beans or joists had being eating by the POWDERPOST BEETLES. The most critical one is supporting 3 beans and is attached to 2 others beans next to a non-working fireplace. The floors I removed were not uneven.

--Iíd really appreciate any advice on how to replace or reinforce- this bean.

This is a link to some pictures

http://s423.photobucket.com/albums/p...t=8422f727.pbw

The measurements of the weaken wood bean are 4x8 6 foot long (this is a real 4 inches wide and real 8 inches high, 100 year old piece of wood).

This is the basement floor, bellow there is a 7-foot high cellar, and above there is the parlor floor and a second floor as well. The house has a brick frame.

I had some general contractors to take a look at it but I would like to have the opinion of an engineer or somebody that has experience replacing/ fixing beans or joist from brownstones and knows how to calculate the load of a beans.

Bellow are the advices I was given already.

Option 1

Leave the old bean, put 2 new 2x 8 Douglas fir wood bean 10 inches away from the old one and attached the bean with galvanize top flange joist hanger. My doubts are: 1a) is Douglas fir strong enough? 1b) should a stronger grain or use engineered laminated wood bean instead?
1c) Are galvanized top flange joist hanger strong enough or should I have an iron shop to fabricate a special L shape flange and use bolts to tight this new bean.-

Option 2

Same as option 1 but use a metal bean instead of wood. This option is very expensive and Iím not sure if itís worth it. Is this bean carrying a big load since itís holding 3 other beans (floor joist) and there is 2 more floors above in the brownstone that justified to use metal?

Option 3

Reinforce the old bean with a C channel underneath and have a special iron hanger to hold the C channel to the lateral beans beans. I did not found any iron shop that wanted to do that yet.

Any advice would be very much appreciated since Iíd like to have my floors back.

Thank you in advance.


<a href="http://s423.photobucket.com/albums/pp314/juanchodiaz/bean/?action=view&current=8422f727.pbw" target="_blank"><img src="http://s423.photobucket.com/albums/pp314/juanchodiaz/bean/th_IMG_0445B.jpg" border="0" alt="JOIST - BEAN" style="width: 160px;"></a>

Ron6519 04-11-2010 02:18 PM

Get a structurally equal beam to replace the damaged beam and use joist hangers to replace the tenon connections.
Ron

Daniel Holzman 04-11-2010 03:06 PM

First off, the structural element you refer to is a BEAM, not a bean. A bean is a type of food you cook and eat.

Second, I agree with the above post, get a structurally equivalent element and connect with Simpson hangars to each of the existing joists. A wood element makes the most sense, simplest to install.

Last, how do you know the damage is by powderpost beetles? That usually requires an expert to determine, you gave no indication that an insect expert had performed an inspection. If this is beetle damage, are the beetles still active? It is critical to insure that there are no active insects continuing to damage your structural elements.

jpcada 04-11-2010 03:53 PM

What kind of wood would be a structurally equal beam?
 
Quote:

Originally Posted by Ron6519 (Post 427169)
Get a structurally equal beam to replace the damaged beam and use joist hangers to replace the tenon connections.
Ron


What kind of wood would be a structurally equal beam? Anyone has any idea. What I can get on the market is only douglas fir.

kwikfishron 04-11-2010 04:00 PM

We bulit the West with Douglas Fir.

Snav 04-11-2010 04:04 PM

Douglas fir is quite common and will work fine.

jpcada 04-11-2010 04:11 PM

What wood fir matches structurally wood used in Brownstones 100 years ago?
 
Quote:

Originally Posted by Daniel Holzman (Post 427187)
First off, the structural element you refer to is a BEAM, not a bean. A bean is a type of food you cook and eat.

Second, I agree with the above post, get a structurally equivalent element and connect with Simpson hangars to each of the existing joists. A wood element makes the most sense, simplest to install.

Last, how do you know the damage is by powderpost beetles? That usually requires an expert to determine, you gave no indication that an insect expert had performed an inspection. If this is beetle damage, are the beetles still active? It is critical to insure that there are no active insects continuing to damage your structural elements.

Thank you for your comments and I apologize for my rice and beans typo, but you had one on your posting too; "hangars", I guess you meant hangers.

The beam was treated by a Pest control company with BORACARE.

I don't know what kind of fir is structurally equivalent element to a wood beam used in a brownstone a 100 years ago. Do you know it by any chance? Everybody sells only douglas fir.

Thank you for your help in advance,

troubleseeker 04-11-2010 04:35 PM

My first thought is "How sustantial is the damage"? From the pictures, it appears to be more superficial; can you stick a screw driver or awl or such into the beam; is it solid when you whack it with a hammer, or does it have an obvious hollow feel or sound to it. If it has decent "meat" left, and you are confident the insect infestation is old damage (Spend a few $ for reputable exterminating company to inspect and treat the area anyway), I would not take it out. When you have a replacement piece of stock, support the headered joists with a temporay wall below and a 2 x 8 "strap" across the tops, then shorten them enough to slip the new timber in the pocket. You can lag bolt it to the existing beam, lag into the ends through the abutting floor joists, and use hangers on all the connections. Get a Simpson catalogue and you will see that they make products that are heavy duty for timber connections, not just the typical sheet metal hangers you see in lumber yards.
A lumber yard should easily be able to get you a timber close to that size. Another source would be a local demolition/salvage company.

That is awsome. I have worked on a few old houses where the framing was all mortise and tenon and pegged or wedged; balloon framed with 25' studs that were tenoned into the sills and top plate. I am still in awe at not only the amount of labor for this, but the skill. The joints all looked like furniture fits.
We had to replace some rotted sills, and I felt as if I were commiting a mortal sin every time I sent a saw blade throught one of the tenons.

jpcada 04-11-2010 05:17 PM

LVL (laminated veneer lumber) to replace a beam?
 
Quote:

Originally Posted by troubleseeker (Post 427219)
My first thought is "How sustantial is the damage"? From the pictures, it appears to be more superficial; can you stick a screw driver or awl or such into the beam; is it solid when you whack it with a hammer, or does it have an obvious hollow feel or sound to it. If it has decent "meat" left, and you are confident the insect infestation is old damage (Spend a few $ for reputable exterminating company to inspect and treat the area anyway), I would not take it out. When you have a replacement piece of stock, support the headered joists with a temporay wall below and a 2 x 8 "strap" across the tops, then shorten them enough to slip the new timber in the pocket. You can lag bolt it to the existing beam, lag into the ends through the abutting floor joists, and use hangers on all the connections. Get a Simpson catalogue and you will see that they make products that are heavy duty for timber connections, not just the typical sheet metal hangers you see in lumber yards.
A lumber yard should easily be able to get you a timber close to that size. Another source would be a local demolition/salvage company.

That is awsome. I have worked on a few old houses where the framing was all mortise and tenon and pegged or wedged; balloon framed with 25' studs that were tenoned into the sills and top plate. I am still in awe at not only the amount of labor for this, but the skill. The joints all looked like furniture fits.
We had to replace some rotted sills, and I felt as if I were commiting a mortal sin every time I sent a saw blade throught one of the tenons.


Thank you.

I hired a local pest control company and they used boracare to treat this beam and some others that were affected. The beam sounds good and the damaged area was removed already, but it has a crack in the middle as shown in the picture.

I'll sister joist the rest of the beams but this case in particular seems more delicate since it's a mortise-and-tenon floating in midair and filled with bricks in front of your fireplace. Should I use an LVL (laminated veneer lumber). They are engineered to carry loads and are very stiff. Should I bolt it to the old joist? http://www.gp.com/build/product.aspx?pid=1392

Ron6519 04-11-2010 06:15 PM

Quote:

Originally Posted by jpcada (Post 427205)
What kind of wood would be a structurally equal beam? Anyone has any idea. What I can get on the market is only douglas fir.

You might need an engineered beam, such as an LVL or a glulam. You would need to speak to someone who is versed with the structural equivalent.
Ron

tpolk 04-11-2010 06:26 PM

from pics i dont see anything that needs replacing. why do you think the wood is defective?

Snav 04-12-2010 09:14 AM

It's purely my opinion - but any wood that has been infested, past or present, should be replaced. There's no real way of knowing 100% whether the infestation is completely inate and old - powderpost beetles are attrocious.

The females lays the eggs and the larvae can live in the larval state for YEARS in the wood and eat continuously. Often people only find out about the beetle when the larvae finally grow into adults and leave the wood through a pinhole sized opening. Upon the emergence of the adults, females will lay more eggs in the wood and so on it goes - over years the wood can be reduced to nothing.

So, if you see exit-holes that just means that the larvae have gone through a full cycle at least once - and it's likely that any larvae left behind are still active and eating, further weakening the wood.

To be honest with you - since you already have the entire floor ripped up I'd just remove and replace EVERY joist that shows damage in the entire area - futher, yet, remove every single post and pray the beetles aren't in the wall-wood, as well. . .replace with treated lumber.

Yoyizit 04-12-2010 09:24 AM

Measure the deflection of the beams at midspan using a stretched line.
Label the readings taken from the damaged beams [D] and the undamaged beams [U].
Assuming equal loading, there may be no statistically significant difference between them [I have a table to use to do this test] which would imply the damage to some beams is superficial.


Also, I recommend measuring the deflection at midspan with and without you standing at midspan. Knowing your weight and the beam dims, the E can be calculated using this concentrated load. The E value may come in handy if you want to reinforce the damaged beams.

troubleseeker 04-12-2010 09:57 PM

Quote:

Originally Posted by jpcada (Post 427231)
Thank you.

I hired a local pest control company and they used boracare to treat this beam and some others that were affected. The beam sounds good and the damaged area was removed already, but it has a crack in the middle as shown in the picture.

I'll sister joist the rest of the beams but this case in particular seems more delicate since it's a mortise-and-tenon floating in midair and filled with bricks in front of your fireplace. Should I use an LVL (laminated veneer lumber). They are engineered to carry loads and are very stiff. Should I bolt it to the old joist? http://www.gp.com/build/product.aspx?pid=1392

It is very common to see shrinkage cracks in large timbers, both new and old. There can be no harm in through bolting instead of lags, and if you join the ends of the new header (where the old one is tenoned), and the joists to the new beam, with pieces of 3" x 3" aluminum angle , I cannot envision a problem. I had previously mentioned looking at the Simpson catalogue for structural hangers, but any saddle types are going to be sized for modern dimension lumber, not the old full cut dimension stock you have. As for your strength worries, think of it this way; right now all the load on the header is actually being carried by the tenons themselves, so a full depth bolted angle clip will certainly suffice.

Dyoung 04-13-2010 07:46 AM

JPCADA

Where are you located? This might help in answering your question. Im a student of timber framing and have been doing a lot of hands on work. Your question is far different than a typical 2x4 stud scenario with respect to the beetles.

Cheers
Drew


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