1910 Beach Bungalows: Replacing all joists & subfloor on imperfect sill plate
Hi folks, this is my first post, thanks for having me.
I’m in the midst of renovating my beach bungalows in a NY beach town. These were built circa 1910 and are in decent condition, for the most part. They are 12.5’ wide by 25’ long, one-story. There isn’t much to them; they are glorified sheds from a decade ago. A photo:
The existing joists are 2×6’s (actual) on a 4×6 “sill plate”, as per the illustration/photos below. There is no rim joists. On top of these was the original tongue & groove flooring with no subfloor. These joists have various issues: undersized for their span, filled with rusty nails from the old floor, and most notably, most are rotted.
The existing sill plate (4”x6” actual) is in great shape (no rot). The sill is supported by wooden piers/piles dug into the ground – I am not yet sure how deep.
The plan is to replace all of the joists with 2×8’s at 16” centers, installed onto the existing 4×6 sill plate. Then ¾” ply and wood flooring.
A few issues & concerns:
The sill plate is not perfectly level, probably because a couple of the wood piers/piles that the sill plate rests have rotted, and the sill sagged. Maybe +/- 1/2″ at most. In the spots where the piles rotted, I am installing concrete piers to below the frost line (w/ sonotubes etc.) to re-support the sill. Eventually I will replace all of the piles.
Replacing the sill plate is not a good option due to time constraints.
Because there is no rim joist, it appears the existing joists were nailed to the studs to keep them vertical until the floors were added.
1. Can I shim under the new joists, between the sill & joists, in preparation for the new subfloor? Or must I shim on top of the joists, or plane them down. It would be much easier to shim underneath. I am not sure what would be best to use for these shims.
2. How can I attach the new joists (& shims) to the sill plate, since there is no rim joist? I was thinking to toe nail them, 1 or 2 nails each end, then use 2×8 blocking between each of the new joists.
3. Another idea was to bolt a 2×8 or similar alongside the existing sill, slightly above the sill, to provide a new flat surface to install the joists upon.
These photos & others can be viewed here: http://imgur.com/a/ps41q
Looking forward to getting this work underway.
P.S. Yes, the vinyl siding is coming off!
Replies
I was thinking about using ledgers and hanging the joists with joist hangers like a deck. This seems rather easy, but I would want the walls tied together tightly. Your old system did tie the walls together quite well. But hey, I'm no builder, just a guy on the internet with a keyboard. Maybe I gave you an idea you can improve on. I would level the structures before proceeding with the floor work, even if it's only temporary leveling.
Foothings
I'm not sure how much work I'd do here without verifying that the footings have life in them. At least dig down a foot or so and check for rot - Most rot in buried posts occurs near the surface where there's air for the microbes to breathe. Consider TechnoMetalPost helical piers - They'll be way easier than digging and pouring in tight quarters.
Yes, you can shim below joists. And blocking between them can work in place of a rim. I'd use treated joists.
Are you getting permits for this? The building department might have its own ideas, particularly near the water.
like its been said, now would be the time to level out your beam. Even if you dont replace the piers right now, it will be MUCH easier to do now.
inspections or not, you should really consider upgrading those floor joist to 2x8's if not 10's. that crazy looking 4x4 or something like that running down the middle on some blocks was retrofitted for a reason. those floors were probablly like a trampoline.
you can shim from the bottom but if you upgrade to 2x8's you can use a cleat on the beam, knotch your new joist and still mimic the old system.
Yes, the old floors were like a trampoline.
3 weeks later, here is an update:
I took your advice (and that of others) and re-supported the sill beams. Each 12'x25' bungalow now sits on fifteen 12"-diameter concrete piers, installed to 42" below grade.
The new floors will have a 3rd 4x6 beam running down the center, also installed upon new concrete pier foundations. This cuts the joist span down to ~6'.
The aforementioned sill beams were secured to the piers with Simpson deck connectors and 4x4 lumber. The beams are now level within approx. 1/4", and I am pleased with that.
Anyway.
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(Photo is here)
I was hoping to solicit advice regarding a new problem: how to repair the rotted ends of the 4x6 sill beams? The back sides of the bungalows were subject to water intrusion that rotted about 12" of the otherwise-strong sill beams. We cut that out and got back to good wood.
How can I repair this beam? The load is not tremendous, and the next concrete pier is only 10" away. Maybe:
a) Add new 4x6 lumber in line with the existing good wood. Connect/sister both the new & old beam with 2x6's on both sides, drill staggered holes, & bolt them together.
b) The same as the above, but instead of thru-bolts, use ledger lag bolts or similar (I like this).
c) The same as above, but instead of putting the 2x6's on the sides, install them top & bottom.
d) Install dowels & epoxy. I don't like this because I want to make the repairs starting tomorrow, and I'd need to find proper dowels, epoxy, & methods overnight.
Alex
Beam between 2 piers under the rotted section
If you have room between the piers and the beam, just put a new beam underneath the existing beam, running between two adjacent piers. Full structural support in bearing without relying of fasteners. Can be doubled 2x6 with or without spacers.
Run a few 10" spikes down though the existing beam to the new one to tie everything together.
Replace the cut out section with doubled 2x6 to support the floor joists.
That is wise & obvious.
Makes perfect sense, also simple.
Are you talking about spikes aka 3/8" x 10" galvanized spike nails? (These or similar.) How the heck do you drive those in ...
Only problem with that is it would block acess to the sewer main undserside the floor, alongside the repair area. Which would be an issue if I ever needed access for repairs.
Again, very simple.
Thank you for the sketch.
I think a 12" 4x4 as a bearing plate is wise. How to connect the spiced beams to the bearing 4x4? Any advantage of long nails vs ledger bolts in this instance?
Cheers. Will update with photos soon.
If you can get the beams to bear on the post by 1.5" on each side, the 4x4 bearing plate is not required. Just use a 4x4 post cap and a thinner strap above that to tie the two beams together.
if you do need the bearing plate, use a 4x4 post cap the tie the plate to the post. Join the two beams with the metal plates, and then either:
spike down into the bearing plate through the beams
use Timberlok screws instead of spikes
strap beams and bearing plate together ( some posts caps will work here)
toe nail using 4" or 4.5" nails (20d or 30d)
Cheers,
An update as promised
Nothing too exciting, but you folks helped convince me to do this the right way, so here are some photos.
Here we are digging for & installing the sonotubes.
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Here we are, after the tubes were installed, digging for the new water main. Beefy 1" PEX buried 42". I would have done this at the same time that we dug in the concrete piers, but there was no room, and the sand has a tendency to cave in upon itself.
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And here are the supports. From left to right: temporary, old, new.
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Besides that, there were some problems, but they've been handled.
And of course, my questions:
Is there any reason that I shouldn't use hurricane ties such as the following to secure the new joists top the sill beams? Advantages? You may recall from, before that there is no rim joist to nail the new joists into. I wam planning hoever, to add blocking between the joists, so it seems that the main role of the hurucane ties (or toe nails) is to keep the structure square & tied together.
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Lasty, what the heck was this block in the wall for? I removed it and saw no purpose for it.
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Cheers.
That looks like it was a lot of work!
Regarding the joists: no need for the hurricane ties, but will do no harm. They are intended to tie roof rafters onto the side wall. For balloon framed structures, the joists are usually nailed to the wall studs, and toe nailed to the sill. Blocking is installed between studs resting on the top of the joist, or between the joists butted up against the studs. If the joist spacing is not the same as the studs, just toe nail to the sill, and then add blocking. the blocking stabilizes the joists, and off the air flow from below the floor into the wall cavity. This blocking is the fire stop, and stops air migration into the wall if you are insulating.
If you are concerned with hurricanes, then the roof rafters are tied together at the ridge, tied to the side wall, and and the side wall is tied to the sill. The sill is already tied to the concrete piers, and that is about a good as you can get it.
Regarding the block wall: I see a hole in the wall, which to me looks like a stove pipe exit. If there was a wood stove in there at any time, the blocks would be the fire barrier.
Cheers,