Repair cracked stair tread...

[blueman]

One of the 12" wide treads on our main staircase has an ~18" longitudinal crack in it. As per an earlier thread, the consensus seems to be that these treads are 150 yr old heart pine.

Here is a link to a pic: http://96.252.37.8:8080/public/1stFlrTread.jpgI am not concerned about the visual look of the crack (if anyting it adds "character") but the area under the crack is not well supported and gives a bit when you put weight on it -- in fact, the absence of such support may be the proximate cause of the crack. The crack has probably been there for many years.

Since replacing the tread is not easily feasible given the old wood, I would like to repair the tread.

Now removing the tread would not be easy since 2 balustrades are toenailed into the other side of the tread and removing the entire bannister and balustrades *seems* to me to be a big job.

So, I was thinking it might be easier for me to access the underside of the tread from the alcove underneath the stairway by cutting through the plaster and lathe on the underside of the stairway. My idea would be to expose enough area so that I could slip another board underneath the tread to span the crack and add support.

To secure the support, my thought was to cover it with glue (either polyurethane or epoxy). Assuming that I won't be able to get good clamping pressure from below, I would run some temporary small gauge screws through the face of the tread to temporarily clamp the tread and support board together. Alternatively, I could try to expose more of the stair underside at the risk of creating more mess and a bigger plaster repair job.

Before, I go cutting into the plaster and lathe, I wanted to get advice on whether this is a good approach along with any additional advice or pointers. Of course, I am open to *any* other better suggestions.

Thanks

[Nonny]

Good plan, IMHO. When reaching the underside, I'd do as you plan with the crosspiece and screws. However, I'd dry fit the entire cross piece, including the screws. Then, I'd remove it and 1) fill the crack from above with 30 minute epoxy and 2) slather on Liquid Nails from below before reinstalling the crosspiece and all screws. I'd leave the screws in place, then repair the plaster.

[blueman]

Yes - I was considering filling the crack with epoxy - though I would probably use West Systems with some filler to get the right viscosity.

Alternatively, maybe the crack would look better to leave natural and consider it as "character" since I don't think I will get much structural strength from filling the crack with epoxy given that the crack seems quite old and weathered meaning that it doesn't seem like it will draw together tightly to give a good bond. Since much of the force comes from stepping on the crack, I think the real strength will come from the supporting piece I plan to place underneath.

Would Liquid Nails be stronger/better than Epoxy or Polyurethane? I guess it might depend on how flat the bottom of the tread is but just curious about what would give the best adhesion assuming the bottom of the tread may be a bit rough.

I doubt I will have enough space to put the scews in from below. So, I was assuming that I would need to drive the screws through the top face. If so, I was planning on removing the screws after the repair so as not to mess up the aesthetics. Although, perhaps I should use trimhead screws, countersink them and fill the holes with tinted woodfill of some type...

Can I assume that even if the underside of the tread is rough or a bit uneven that a well glued and clamped board underneath it will provide adequate support after the screws are removed?

[GROVER]

My posting does not address the structural aspect of the problem, which of course is what needs to be solved first. Others have already posted good suggesions. I remember a show in which Norm repaired a gaping hole in a re-used barn board by filling it a two part epoxy which he tinted black (no attempt to match). You could open up the crack with a veining bit in your router and fill and sand.

Joe G

[blueman]

Interesting idea.

I'm not sure the router approach would work since the crack goes up to the skirtboard and my (full-size) router probably wouldn't let me get any closer than 4" or so.

Also, I would be concerned that a routed groove would look to "regular" and unnatural.

Maybe better for me to use my dremel to clean out the crack while also letting the "unsteadiness" of my hands keep the look more natural...

Thanks for the suggestion!

[news]

An episode of Ask This Old House showed a product (stepped wood pins) and their associated special drill. I think this is the product:

[Lew Hodgett]

If you truly mean, "I am not concerned about the visual look of the crack", then the repair is fairly straight forward.

Using a Fein MultiMaster with a straight blade, plunge completely thru the tread in the crack, then clean out the crack at least 1/8" wide or what ever is necessary to remove all damaged tread material.

The width of the cut is not important as long as it is wide enough to allow the thickened epoxy to freely flow and fill the cut.

On the bottom side of the tread, cover the saw cut with some duct tape which gets removed later.

Mix up some SLOW epoxy, thickened slightly with micro-balloons, and pour into crack about 1/4" deep. (Just enough to seal the cut completely against the duct tape.

Wait 24 hours, then mix up more thickened epoxy and complete filling the cut proud.

Wait 48 hours, then sand smooth and remove duct tape from bottom.

When the tread returns to compost, the epoxy repair will still be in service.

If color is important, you can play around with some artists dry pigments to try and match tread color.

Have fun.

Lew

[blueman]

I actually meant I am not concerned about the visual look of the crack so long as it looks like an authentic crack that comes from "natural" aging and wear-and-tear. A number of the wide pine boards in some of our rooms have cracks (though they are well supported by the sub-floor) which I have been told are considered to be a "plus" rather than a defect to be repaired.

I'm not sure I am crazy about the look of an obvious epoxy repair on our front stairs -- though perhaps with tinting and shaping, I could make it look more natural...

Damn I just bought a Harbor Freight variable stool multifunction tool and I so want to use it so I can validate my tool buying craze to my SWMBO.

And I love playing with all my West System potions...

Yeah, but I think I will have to resist the temptation to do it the fun way and instead try to make the repair less visible by accessing the underside of the stairs.... less fun though and I really don't enjoy ripping out and then replacing plaster-lathe...

Thanks for the suggestions and particularly the epoxy instructions -- they will definitely come in handy on many future repairs...

[Sonny]

From what you have described, plaster and lathe, I wouldn't think the plaster and lathe is along the bottom of the stair stringers, but encases some cavity under the stairs. Since you will open that area, why not finish the interior, there, for storage or other and create an access door, concealed, maybe, if an obvious door would not complement the surounding design/decor/trim.

If there is such an area, accessing a tread should not be an issue, in order to secure the tread easily.

Sonny

[blueman]

Actually, the area under the stairs is now open with the plaster & lathe underside of the stairs closely following the rise of the stairs.

I have often thought about enclosing the underside to add storage but the stairs are parallel to a narrow hallway and I am concerned that closing off the underside may make the space feel more constricted. Not sure though and will likely consult an architect at some point or draw it all in sketchup ;)

[-MIKE-]

If that's the case, and you can get to the underside of this tread, seems like an easy fix.

[Larry Jaques]

On Mon, 8 Feb 2010 04:26:30 -0800 (PST), the infamous Sonny scrawled the following:

C'mon, guys. A lathe is a roundyround tool. Lath is a stick used in construction.

I second the additional storage suggestion.

For the fix, I'd glue and screw a board to the bottom of the cracked tread. I'd fastening the board to the front riser under the tread with a screw, and to the back of the next riser via another board coming down, also glued.

-- We don't receive wisdom; we must discover it for ourselves after a journey that no one can take for us or spare us. -- Marcel Proust

[blueman]

I finally got around to fixing the tread...

I was just about to cut in through the plaster and lathe on the underside of the tread, when I had second thoughts about the mess and pain of repairing it all and having to repaint the entire underside (since the off-white ceiling paint would be almost impossible to match).

So, I decided instead to probe and clean out the crack first. On probing, I realized the following:

1. The tread over the crack seemed to be supported either by a piece of subflooring or by a wide stringer
2. I was able to clean out the crack pretty well
3. The tread itself seemed pretty thick

So, I then decided to mix up a batch of my trusty West System epoxy. I first dropped in a fair bit of loose epoxy which do to its low viscosity mostly dripped down through the crack -- my hope being that it wouldn't all be lost but would server to bond the tread better to the stringer and/or subfloor piece. I then added some colloidal filler and filled the crack.

This seemed to really solidify the tread and so far is holding well (and also looks pretty good).

If this repairs doesn't last, I will go back to my original plan of cutting in from below -- but meanwhile it seems to be working both physically and cosmetically...

[Matt]

The URL for the pics doesn't work ... (for me at least)

Your fix sounds good - you should send your story in to West's Epoxyworks

Matt