vanblah

My wife has decided that we need to remove a wall between our kitchen and breakfast area.

The span is about 8 feet. It's just under the outside wall of the second floor of an airplane bungalow.

Anyone here know whether it would be worth it to get a couple of 10" lam beams or would it be ok to just sister a couple of 2x10 or 2x12's together.

I know that lam beam is supposed to be stronger ... but I've heard of the glue failing in them under certain loads. Our house is 80 years old so most of the settling is done by now.

arch13

GluLam, GluLam, Glulam.
Have I said it enough times yet? Despite what contractors love to tell clients, a sistered beam has only 1/4 the shear ability of Laminated lumber, or even better, actual lumber.

Take it from an architect, you will regret using a sistered beam. Besides, and 8' span is quite a small amount of work to laminate if your making the lam beam yourself.

But why don't you just buy an 8' peice of 10"x6" laminated strand lumber ? The price is low if you can't afford actual lumber with a large nominal size, and it has quite the compressive and shear ability.

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black94lt1

Glue lam if you can get one (it should be instock at good lumber yards). that is a pretty small span, so if it does not work out, conventional dimensional lumber will do fine, but lams are superior.

slant eyes

sorry for sounding ignorant. but what are glue lams and sistered beams? when i first read sistered beams, i thought he meant stacking more than 1 2x4 2x6 2x10 or what not, then you made mention of actual lumber.

i'm not planning on knocking down a wall, but there is never too much education right?

thanks

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arch13

Sistered beams:
Take say two 2x10's. Place them end to end. Now overlap/stack the two ends by say 10" to 1'. Now they are sistered. Nail or screw them like that with wood glue, and they will act like a single beam in many instances.
Your floor joists are made like this.

Glue lam:
Not even lumber. Kind of like plywood, but not. Far stronger, engineered, expensive. Made from wood, but not the kind of thing you go down to home depot to buy. You'll need to source them from a good lumber yard. Strong, also, ugly.
Glue lam I beams are made from wood parts, and are at around 1/2 the compresive weight and span ability of same size steel. That's impressive.

Actual lumber:
exactly what you think I mean.

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slant eyes

thanks for the time to clarify. one more thing to clarify on my end, if you have the time. so the sistered beams are merely end to end with some overlap...like...

--------------------------_______________________ with a bit of overlap right?

and not stacked like this:

_____________________________________
_____________________________________
_____________________________________

and glued down or nailed or screwed or bolted or however you want?

and arch, you mentioned that you're an architect. not meaning to thread jack, but a small project of mine this summer would be to throw away the lil pre-fab tool shed in the backyard, it's really weathered bad, and replace it. parents wanted to know if they should buy a new one and i said, for that money, i could lay a 2 inch concrete perimeter and build actual walls so it would seal out all the pests, ie rodents, snakes, and whatever lives on the side of the hill. any pointers before i get started and have to tear it down? thanks again.

i have a friend locally that is an architect as well, but he only does commercial buildings. i was gonna ask if he could draw me up something in cad so i can see what i should build. but don't know, i might just wing it.

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arch13

Exactly.
They need to be fixed together to prevent all movement (Screwing is most effective) so that they can spread their load carrying accross the entire surface. You put a ton of wood glue then screw them down while the wood glue is wet.

And that is how you make a sistered beam

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vanblah

I picked up a 3.5" x 12" x 12' lam beam yesterday.

My idea for sistering would have actually overlapped the entire length of the 2x10. Sistering really means just using two or more pieces of lumber side by side. You can overlap just the ends or the entire length:

http://www.hammerzone.com/archives/f...st1/sister.htm

canucker

I attached a steel beam via bolts to the existing beam with supports on each end. Engineered and approved by the city.

Before:



After:

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slant eyes

looks cool. i'm curious tho, how much does a steel beam like that cost? i work as a rigger/ground rigger and am having to hang motors from the beams but never really thought to have it installed in a residence. we have 2 rooms here that are small and would like to knock down the wall too.

crazy thing, we had a 3,000 lb beam at a certain arena. when madonna came in, we hung a floating catwalk from the beams and were told that the catwalk and dancers on the catwalk weighed at most, 2,100 lbs. so all was good right? well the weight was a static weight. turns out what they didn't tell us was that the damn dancers would be bouncing up and down. bent the beam.

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cj2112

ummm they were dancers....didn't anybody think that they might actually be dancing?

slant eyes

dancing...yes. bouncing...no. plus we as locals can't know the weight of every concert that comes through town, it is the job of the roadies to tell us this. that's why we ask them and that's why they get paid what they do. we were told by the show rigger that it is max 2100 lbs. so that's what we went with.

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