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loft platform support joint

5.5K views 23 replies 5 participants last post by  Bushwhacker  
#1 ·
I'm working on this house for a customer. The previous tenant installed a post in the middle of the loft for support. She wants the post removed but the support retained but made of cedar to look like it is supposed to be there.

My plan is to put a 6' - 2"x6" between the existing 4x6 supports (flush to the wall), then add an additional10' - 2"x6" or 4"x6" down the middle parallel to the existing 4"x6's. (same thing on the other end of the new 10' support)

So my question is what kind of joints would you recommend connecting the new 10' support to the new 2x6 and then one kind of joints connecting the new 2x6 to the old 4x6?

It would be pretty strait forward to use a mortise & tenant joint to connect the new 10' support to the two new 2x6. But what about the joint to connect the new 2x6 to the old 4x6? I don't want to use Sampson tie joist hangers as they would look bad. I could use pocket screws, but I don't know where to get rough cedar plugs to fill the holes.
I just realized that I could remove the decking and use a type of mortise there too. Not sure what its really called but I'm picturing notching a slot out of the 4x6 that a tenon would slide down in from the top.
What kind of dimentions would y'all recommend for the size of the tenons in each joint?

thanks
Everend

PS. I think this would be my first use of a real mortise and tenon joint.
 
#3 ·
whole bunch of missing information...

what are the spans???
what is up in the loft..
how tall is the post..
what kind of base...

She wants the post removed but the support retained but made of cedar to look like it is supposed to be there.
take out the 4x4 and replace it w/ cedar column??

My plan is to put a 6' - 2"x6" between the existing 4x6 supports (flush to the wall), then add an additional10' - 2"x6" or 4"x6" down the middle parallel to the existing 4"x6's. (same thing on the other end of the new 10' support)
not really sure what you are saying??
two piece beam joined together at the top of the post???

So my question is what kind of joints would you recommend connecting the new 10' support to the new 2x6 and then one kind of joints connecting the new 2x6 to the old 4x6?
If I read this right..
open the wall and build a layered column out of 2x4's to hold up the end of the new cedar beam...
make the beam to column connection w/ a metal beam saddle bracket..
there a lot of variations and this one some serious heavy duty..
Image

It would be pretty strait forward to use a mortise & tenant joint to connect the new 10' support to the two new 2x6. But what about the joint to connect the new 2x6 to the old 4x6? I don't want to use Sampson tie joist hangers as they would look bad. I could use pocket screws, but I don't know where to get rough cedar plugs to fill the holes.
that's tenon.. and if I got this right...
mortise (notch out) the bottom of the beam an inch or so as a receiver for the blunt end of the column...
T plate them together and through bolt the plates..
antique the plates, leave then as is or paint the...
use the saddle bracket...
the pieces I showed you are meant for exposed timber framing...
the Simpson strong tie would be perfect for the ends hidden in the wall..
Image

I just realized that I could remove the decking and use a type of mortise there too. Not sure what its really called but I'm picturing notching a slot out of the 4x6 that a tenon would slide down in from the top.
HUH???

What kind of dimensions would y'all recommend for the size of the tenons in each joint?
not a clue w/ out more details and measures...

NOTE:
I'm not seeing the use of the 2x6's...
you know you could put in a beam w/o the support if you see fit to do that...

Floor Beam Span Tables | Calculator
Engineering Data - Real Cedar
UMass Amherst: Building and Construction Technology » Understanding Loads and Using Span Tables
 

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#24 ·
Loft support

whole bunch of missing information...

what are the spans???
what is up in the loft..
how tall is the post..
what kind of base...



take out the 4x4 and replace it w/ cedar column??



not really sure what you are saying??
two piece beam joined together at the top of the post???



If I read this right..
open the wall and build a layered column out of 2x4's to hold up the end of the new cedar beam...
make the beam to column connection w/ a metal beam saddle bracket..
there a lot of variations and this one some serious heavy duty..
Image



that's tenon.. and if I got this right...
mortise (notch out) the bottom of the beam an inch or so as a receiver for the blunt end of the column...
T plate them together and through bolt the plates..
antique the plates, leave then as is or paint the...
use the saddle bracket...
the pieces I showed you are meant for exposed timber framing...
the Simpson strong tie would be perfect for the ends hidden in the wall..
Image



HUH???



not a clue w/ out more details and measures...

NOTE:
I'm not seeing the use of the 2x6's...
you know you could put in a beam w/o the support if you see fit to do that...

Floor Beam Span Tables | Calculator
Engineering Data - Real Cedar
UMass Amherst: Building and Construction Technology » Understanding Loads and Using Span Tables
I agree with Stick, you could use a beam. I tore out a load bearing wall between my kitchen and the living room and replaced it with a 16' 6" beam. Made out of 2x8s with 1/2 " ply sandwiched between and scatter nailed with lots of glue. If you reverse the crowns and clamp it together it will be very strong.
 
#4 ·
OK well the platform is about 6' x 10' the issue with the original design is the floor decking is 6' long 2x6 only supported on each end where they rest on the Cedar 4x6.
The tennant who lived here added that center pine 2x8 joist and a 4x6 post in the middle.
The walls are tongue & groove 8" wide pine. I really don't want to open the wall. Also the other end of the platform has a window under it. So even if I did open the wall to support a new beam I would need to make sure the header over the window is sufficient.
 
#5 ·
You didn't say how much headroom there is, under the 'beam'(?).
I agree with you, Everend, those Simpson ties look awful.
If you have the headroom available, I'g recommend putting in a proper beam...4X6 ...with the 6" dim. being the vertical ht.
A bandsawed wooden bracket, hiding a steel angle bolted to the wall would give you strength way beyond what's needed.
Flat steel plate on either side of the post~beam connection, bolted through and painted the colour of choice would make a classier look. As we say up here 'skookum' as Hell. :)


The pics below are just an illustration; go with what's available to you.
 

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#6 ·
Not sure that last post actually cleared up any confusion. :)
There is nothing on the loft since the house is vacant.
Each time I refer to the decking I mean the floor of the loft.
The existing 4x6 beams are supported inside the walls. They have been sufficient to hold the loft so far. The owner wants the post to go away. I'm not willing to remove the post and that green pine 2x8 without properly supporting the center of the 2x6 loft flooring.
I just realized adding only one beam between the two existing cedar 4x6 would still leave the 2x6 deck boards spaning 3'. That's probably still too wide of a span.
 
#15 ·
I just realized adding only one beam between the two existing cedar 4x6 would still leave the 2x6 deck boards spaning 3'. That's probably still too wide of a span.
any annoying flex can be fixed by taking up the deck and and 3/8 spline the boards...
 
#10 ·
The beam's span is only 6'? Or is it 10'?

In any case, you need to conform to the building code for spans. Saying it's a "loft" doesn't make it any different.
Someone could use it for storing bankers boxes full of old files...piled four high! You as the contractor are responsible; not what the homeowner wants (aesthetics aside).
If it's a 6' span, carrying a 10' deck, or a 10' span carrying a 6' deck, it's still 60sq.' of storage capacity...say at 50lbs per sq.' that's potentially 3,000lbs of live load.
I like to view these situations as worst possible case.
(I don't know how many times I've seen brickies pile a bunch of bricks in the middle of a 2x12 plank...and then walk out there with a bucket of mortar and and start laying brick! Yikes!!)
 
#11 ·
Maybe this helps to clear up the situation. The tenant added the pine noted with yellow arrows. The owner wants these to go away and no post. There was no other support there before the tennant added this. I think the loft deck does need more support.
I propose to add new cedar lumber only where indicated by the blue lines. In my original post I talked about a single new board where the line 2x8 is but now I think that still leaves too long of a span between joists.
 

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#13 · (Edited)
the wall ledger will hold the deck...
if the ledgers are firmly mounted to the
a 4x6 or 6x6 beam down the center will work...
3' of 2x6 isn't going anyplace...

envision the capital letter ''''...

the cross bar is the beam (6x6) and the legs are 4x6's...
build it and slide it up under the the deck...
fasten the legs to the wall studs w/ timberLOK or GRK screws...
fasten the legs to the cross bar w/ a Z hanger, toplface flange beam hanger or a bucket intended for show...
need plugs..
make yur own... Veritas® Tapered Snug-Plug® Cutters - Lee Valley Tools

GRK Fasteners > Products > Structural > Structural
TimberLOK Truss/Rafter to Top Plate Structural Wood Screw - Landscape Timber Screw ? Stair Stringer Screw
 
#20 ·
I cut the boards to a tight fit, then used a framing nailer to secure them in place. Hiding the nails behind the decorative .2" thick steel brackets and ties. The hex bolts are 2.75" long so on the two end boards, they go through the 2x6 and into the T&G covered wall.
Using the decoritive ties really made the difference for me on this job! thanks again for the advise!
 
#21 ·
you should have hit the studs by at least 2''...
you have no way of knowing if the T&G will hold......
 
#22 ·
I don't really know where the studs are behind the T&G. I could probably figure it out on one side based on the location of the outlet. The T&G surface is too inconsistent to give me a good reading on the stud finder and I don't have a thermal camera to find them that way. I could have drilled holes through the wall, hidden behind the boards but I didn't think of that at the time.

The real support for the ledger boards comes from the anchors and toe'd in framing nails on either end.