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A-Frame Rehab

B42985

Student
Jan 25, 2025
4
Currently working on a vacation home we purchased. It’s a ~1979 construction A-frame house in central PA, approximately 1,300 square feet with a concrete block foundation and walkout basement. It was previously used as a hunting cabin with a lot of random supplies and DIY construction. There is a central Steel I-beam about 36 feet long running across the middle of the foundation and supported by the foundation. The I-beam is stamped PHOENIX-USA and has the following approximate dimensions, 7 ¾” web, 4.5” wide flanges. The flanges are hard to measure, but it looks like around 9/16” at the root radius and ¼” at the toe. I can’t get to the web to measure the approximate thickness.

The floor is framed with 2x8 joists spanning approximately 12.5 feet. Joists are placed on wood shims on the concrete block foundation, there is no sill plate. The joists are #3 lumber spaced 24” OC and sitting on bottom flange of I-beam at various depths on the toe, not cut to match flange. The current floor slopes down about ½” - ¾” from the foundation to the I-beam. I can lift some of the joists to level using shims on the I-beam flange, so it seems like a lot of the issue is how the josits are sitting in the I-beam (edge of the toe) and shimmed on the foundation.

The subfloor was laid with ½” plywood and ¾” particle board underlayment, both of which have to be replaced. The subfloor and underlayment meet the I-beam, but do not cross over. I would like to replace the joists with #2 2x10s, however there is no headspace for a top nailer.

Of the approximately 36ft span from the front to the back of the house, the front half is a living room. The back half is a dinning room, kitchen, guest bedroom, and bathroom. The back half subfloor and flooring has been replaced and is level enough, so I’m only working on the front half right now.

I would like to replace the joists with #2 2x10s which will need to be notched to fit at the foundation end. I can either notch at the beam side to fit against the webbing, or pack and install front joist hangers. If I notch at both ends to sit the joists on the flange, I would install blocking to prevent the joists from turning and cut them tight to the web. The I-beam has no existing holes for packing. I would like to run ¾” subfloor about ¼ inch proud of the beam and then add underlayment which would go over the I-beam so that we don’t have cold air coming up from the basement around the I-beam, which is a current issue.

This is a very rural property so I have to work fast (only up for the weekends) and have all supplies on hand prior to starting, otherwise it's an two hour plus roundtrip drive to the store. I’m wary of drilling holes into the I-beam to pack it since I don’t know anything about the I-beam, or have any house plans. Do you agree, or think this would be a non-issue? It seems my best bet is notching the 2x10s and resting them on the I-beam bottom flange.

Additionally, I would like to do one side of the I-beam at a time, since I probably can’t knock out both in a weekend. I have heat going to the basement so that we don’t have to winterize, but I can’t really get it much above 38 degrees when the temp drops negative, which we have had a lot of lately. If I pull the full subfloor to pack the I-beam, I worry the pipes will freeze inside the house, because the way I’m heating I wouldn’t have capacity to keep the inside house and basement above freezing if the temperature drops again. I guess I could also add additional 2x8 joists to decrease the spacing, or sister 2x8s to the existing joists, but shimming on both ends seems a little unsatisfactory. Or I suppose I could use powdered actuated fasteners, or self drilling structural screws to pack the I-beam, but I'm not sure this would be sufficient.

Seems like notching and resting on bottom flange is the best option, but I'm curious to hear other's thoughts. Any constructive insight is greatly appreciated.

Thanks,
B
 
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Additional information. The beam is a total of 9" from the top of the top flange to the bottom of the bottom flange.
 
Is it 36 ft. clear span or is there some columns to break up the span? Can't imagine any beam with those dimensions even coming close to spanning 36 ft.
 
There is one support column about halfway...well, technically a floor jack on a cinderblock. That's also something to be addressed on the rather large to-do list.
 
Thanks for sharing! Some of the joists definitely need to be replaced, but most look okay. However, the floor is pretty bouncy and noticeably sloped because the joists sit on the toe of the I-beam, so about 3/4" below level. I have to replace the subfloor anyway, so I wanted to level the floors before replacing all the flooring. Some of the joists are also only resting about 1/2" on the I-beam.
 
Is it 36 ft. clear span or is there some columns to break up the span? Can't imagine any beam with those dimensions even coming close to spanning 36 ft.
How about answering this question?
 
Thanks for sharing! Some of the joists definitely need to be replaced, but most look okay. However, the floor is pretty bouncy and noticeably sloped because the joists sit on the toe of the I-beam, so about 3/4" below level. I have to replace the subfloor anyway, so I wanted to level the floors before replacing all the flooring. Some of the joists are also only resting about 1/2" on the I-beam.
I would spend the time and effort just sistering as needed then. Focus your effort on improving the bearing condition. Send us a picture of what is there right now.

As for the slope, your options are to sister the entire floor to make it level or shim the subfloor/ flooring to make it flatter. Usually cosmetic improvements are cheaper than doing it structurally.
 

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