Repair Decayed Lower Jamb Joint

Wood repairs for sashes, frames and sills.
oculus
Posts: 66
Joined: May 18th, 2011, 12:15 am

Re: Repair Decayed Lower Jamb Joint

Postby oculus » March 11th, 2012, 3:23 pm

Method #1
Peter Carroll's Scarf & Rebate, contemporary type:

Peter writes:
My method is to loosen the lower ext. casing & blind stop. (which by the way, is generally in the same condition as the jamb). I gently pick off the rot, dry out the space, harden the punk & apply a thickened, non-sagging, epoxy filler. (West, System Three, & ART have epoxies fitting these characteristics)

For a replacement, frankly I've tried all kinds of joints and most have gone over my budgeted time for the repair. I KISS or "less is best" this practice into the following for consideration: Warning! Very non-traditional.
1. Loosen or remove Ext casing. (for visualization/working room & ventilation)
2. Use a simple scarf joint (4:1 optimal/2:1 acceptable) in the Jamb bottom & again higher up on the blind stop. (I have found a butt joint effective in the jamb only & only if it is backed with a butt block of 2" wide X 1/2" thick X full length of joint) Oscillating Saw with fine cut blade & steady hands.
3. Rebate the end of the new jamb (no dado) to accept sill at the proper slope.
4. Apply thickened bonding epoxy to end grains of old & new Jamb/blind stop.
5. Glue & Screw or glue & clamp in place. Clean up access epoxy. (I use clamps & #6 x 3/4" brass wood screws, counter sunk & top filled) If the "fast" acting hardener the epoxy cooks off in 30 min cures in a day.
6. Re-set stop & casing, sand, caulk seams & finish.

I rely on the properties of the epoxy for bonding & waterproofing versus the joinery. Not traditional by any means, however the time for the repair is more predictable and less potential for over runs for the customer.

Longevity.......Don't know. Probably last for my life time & beyond. Technique is used in boat building often. I have a 8 yo wooden boat joined in this fashion that stays in the water or uncover (upside down) 365 days/year in Northern Michigan without any evidence of joints popping.

Paul writes:
There are some issues to consider when introducing wood into this type of window jamb repair, especially if it is to be done with tight joinery & minimum epoxy or other type of adhesive or sealer. Wood species, heartwood, quatersawn, preserving & sealing vulnerable end grain, minmizing fasteners that are susceptible to corrosion are some items that should be considered. There are probably many times when [splice or ] dutchmen type exterior repairs are justified, especially if the wood is not going to be painted or coated with a solid stain & the texture or use of wood is specified for good reasons.
Attachments
011_0001.jpg
Last edited by oculus on March 11th, 2012, 3:30 pm, edited 1 time in total.

oculus
Posts: 66
Joined: May 18th, 2011, 12:15 am

Re: Repair Decayed Lower Jamb Joint

Postby oculus » March 11th, 2012, 3:25 pm

Method #2
John Leeke's lap & dado method, traditional type

John writes:
Rebuild the end of the jamb by splicing on a new piece of wood with the appropriate shape to match the jamb and re-create the joint.
Lap it in if you can take off the casing, lap it out if the casing is staying on.
My way of splicing a new jamb joint with the lap facing out, so it can be made with the exterior casing left in place (although this sketch shows the casing removed). There is the lapped splice at the top of the new wood, and the dado of the joint with the sill at the bottom of the new wood. The top shoulder is beveled, so if the paint weathers off and the adhesive in the joint fails, water would tend to flow out of the joint--that's the traditional detail, in my view water might still enter the joint by capillary action. Sometimes I bevel these weathering joints, sometimes I don't, and have not noticed a difference in performance over the years. It is fun to do the bevel, but takes a bit of extra time and attention.
>>Do you ever have problems getting the bottom dado to sit properly on the sill? <<
No, the dado "clips" right onto the sill, but the the fit (distance between the dado shoulders) has to be a loose fit, much looser than when I make this joint all new when it is a "press fit."

>>Do you use adhesive in the dado?<<

Not if I'm making it an "open joint", so it can be taken apart in the future. I can usually fasten the dado joint with a long screw (3" to 4" or 5") angled into the joint from where the bottom surface of the sill meets the sheathing or siding of the wall. Before placing the new scarfed piece and the screw, I drill a shank hole from the bottom of the sill, angled up through sill and coming out the end of the sill.

>>And add screws to the face?<<

Yes, two shank holes through the new piece, spread the adhesive on the lap and shoulders, place the new piece, screw the new piece onto the face of the lap on the old jamb.

>>I would like the slope of the face cut be part of the standard.<<

I do too for the illustration. We might mention in the text that beveled is good for wet climates and unbeveled would be acceptable for temperate or arid climates.

>> Also the fit must be pretty precise as well.<<
A precise fit at the lap is good. A loose fit at the dado is sometimes necessary to get the new part into position.
Attachments
011_0002.jpg

oculus
Posts: 66
Joined: May 18th, 2011, 12:15 am

Re: Repair Decayed Lower Jamb Joint

Postby oculus » March 11th, 2012, 3:26 pm

Method #3

Angled lap with rebate, traditional type

John writes:
This looks like a variation of Method #2, the procedure to create it would be about the same as #2, with a different design for the lap.
Attachments
011_0003.jpg

oculus
Posts: 66
Joined: May 18th, 2011, 12:15 am

Re: Repair Decayed Lower Jamb Joint

Postby oculus » March 11th, 2012, 3:27 pm

Method #4
Wood-epoxy repair, contemporary type.

Peter writes:
My method is to loosen the lower ext. casing & blind stop. (which by the way, is generally in the same condition as the jamb). I gently pick off the rot, dry out the space, harden the punk & apply a thickened, non-sagging, epoxy filler. (West, System Three, & ART have epoxies fitting these characteristics)

Martin writes:
When the bottom of the jamb is severely decayed I typically resort to a wood block inside the pocket space, screwed to the sill.
The jamb is then fastened to the same block (recessed screws through the jamb above the decayed area), securing the sill and jamb to one another. Then the decayed bottom of the jamb is treated with consolidant and missing wood replicated with wood putty epoxy.

Paul writes:
Many years ago I took the path of repairing most of the exterior wood decay with epoxy & often in conjunction with borates as a preservative. ...these repairs can be mostly hidden & should last for decades with proper maintenance.

Image
Attachments
011_0004.jpg
Click on the image once for better view, then click on it again for close up.

johnleeke
Posts: 375
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Full Name: John Leeke
Location: Portland
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Re: Repair Decayed Lower Jamb Joint

Postby johnleeke » March 11th, 2012, 4:29 pm

OK, thanks Amy.

I've added comments from this discussion to each of the four methods.

I think each one of the four methods above could stand on its own as treatment to be considered for becoming a standard in its own right.

Is someone interested in writing up and submitting one or two of them for consideration as a standard?

If so, leave a message here to let me know, and I'll split them off of this discussion so each can be worked on and considered separately.
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

oculus
Posts: 66
Joined: May 18th, 2011, 12:15 am

Re: Repair Decayed Lower Jamb Joint

Postby oculus » March 15th, 2012, 12:37 pm

So I am starting to draw these out and one question that I have is how does everyone go about dealing with this repair when it involves a weight pocket door? It certainly makes things more complicated.
Amy Harrington McAuley
Oculus Fine Carpentry, Inc.
http://oculuswindow.blogspot.com/
oculuswindow@gmail.com

"Opportunity is missed by most people because it is dressed in overalls and looks like work"-T.Edison

johnleeke
Posts: 375
Joined: April 13th, 2011, 7:34 pm
Full Name: John Leeke
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Re: Repair Decayed Lower Jamb Joint

Postby johnleeke » March 15th, 2012, 12:57 pm

I have done the lap splice around a weight pocket door. It is another complication or layer on top of this repair, but very doable.
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

johnleeke
Posts: 375
Joined: April 13th, 2011, 7:34 pm
Full Name: John Leeke
Location: Portland
Organization: Historic HomeWorks
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Location: Portland, Maine
Contact:

Re: Repair Decayed Lower Jamb Joint

Postby johnleeke » March 15th, 2012, 1:54 pm

Actually it was easier and quicker the time that I worked it around the pocket door, because I could put a C-clamp on the lap via the pocket door.
John
Standards Co-Founder
Standards Editor

http://www.HistoricHomeWorks.com

oculus
Posts: 66
Joined: May 18th, 2011, 12:15 am

Re: Repair Decayed Lower Jamb Joint

Postby oculus » March 18th, 2012, 6:56 pm

Ok John here is the drawing for your method. Let me know if you modifications.
Attachments
jamb-rot.jpg
Amy Harrington McAuley
Oculus Fine Carpentry, Inc.
http://oculuswindow.blogspot.com/
oculuswindow@gmail.com

"Opportunity is missed by most people because it is dressed in overalls and looks like work"-T.Edison

oculus
Posts: 66
Joined: May 18th, 2011, 12:15 am

Re: Repair Decayed Lower Jamb Joint

Postby oculus » March 19th, 2012, 6:08 pm

Ok try this one.
Attachments
jamb-rot.tif
Amy Harrington McAuley
Oculus Fine Carpentry, Inc.
http://oculuswindow.blogspot.com/
oculuswindow@gmail.com

"Opportunity is missed by most people because it is dressed in overalls and looks like work"-T.Edison


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