What else should I consider doing while replacing the floor joists and subfloor in my 1940s farmhouse?
Asked by Fevrosiya Polovinko 
7 months ago
Last Updated: May 25, 2024
Hey everyone,
I’m currently in the process of renovating the floors in my 1940s farm house. I’m replacing the floor, joist, subfloor, and reinforcing everything with concrete and blocks. Unfortunately, I can’t access the area under the floor through the Crawlspace because the house is so low to the ground.
While I have everything torn up, I’ll also be installing a vapor barrier (which the house has never had before), as well as replacing all the HVAC ducting.
Once the subfloor is in place, I won’t be able to go back under there. So, I was wondering if there’s anything else I should consider doing while I have the floor open?
Thanks!
If you have any cast iron or copper plumbing underneath, consider upgrading to PVC or PEX pipes.
Hey , no worries! Everything has been updated, including the electrical components.
Hey ! That’s fantastic news! Wishing you the best of luck.
Purchase a plastic skeleton and conceal it inside.
Yeah, I’ve heard that a couple of times 😂😂
And randomly place a few empty beer cans nearby…
Haha…I was thinking the exact same thing…not that I would EVER admit to it..
Or how about a small treasure chest containing a DVD labeled “Top un”, but when played, it’s actually “Never gonna give you up”. (Inspired by a Reddit post)
Or, on a more serious note, it’s like a tiny time capsule. Take all the newspapers you can find, maybe some news magazines, perhaps a letter, and wrap them individually in plastic. I actually did that once, inserted between wall studs, when I was renovating my kitchen.
Do you even know what a newspaper is? 😉
Rob Pepperidge Farm doesn’t forget, haha!
Okay, genius, just place a laptop with cnn.com open and bury it, or place it wherever you prefer
How on earth did you figure out I was a genius? I usually keep that a secret.
A genius would understand that was sarcasm
Here’s a tip – try spraying it with metallic spray paint first. This way, it will resemble a real skeleton under an x-ray if someone decides to search your house.
You may want to think about concealing any electrical, electronic, or other wiring.
Absolutely! I’m planning on installing an additional outlet and laying an Ethernet cable underneath the house.
I’d personally recommend running all low voltage wiring through Smurf tubing and connecting it directly to your communications demarcation point. It’s always good to plan ahead for potential future expansion.
Hey, as a computer nerd, consider using CAT-8 for faster speeds. Also, check if your routers support 10gb. If not, at least leave some empty tubes for flexibility.
How about running a couple of wiring chases across the width and length? That way, you’ll be all set for any future wire pulling needs.
Make sure to run more wire than you think you need. It’s relatively cheap and better to have too much than not enough, right?
Using small concrete pads for foundation blocks is a more efficient choice compared to using blocks or dirt.
Yes, all the supports have concrete underneath them. We dug down about 10-12 inches.
Nicely done, having the right width is crucial, even though 2-3” might not be deep enough
She is very sturdy now. Previously, the floor was quite bouncy. You could even park a truck inside now
Reat job, 👍
That’s what she remarked.
Spray foam the exterior walls for added insulation and seal off with vapor barrier and rim box.
If it were me, I’d consider having a company apply closed cell foam directly to the ground. This will serve as a continuous vapor barrier that is both easier to install and provides insulation.
I have to respectfully disagree, that doesn’t sound like a good idea at all. Please refrain from sharing that with anyone else. It might be worth researching MCS related to spray foam off-gassing. It also goes against basic thermodynamics. Can anyone explain why it’s a thermodynamic disadvantage to spray foam ANY floor – ever? Let’s discuss.
I’ve been collaborating with several contractors who have been utilizing that specific application for close to 20 years in High Performance Net Zero Homes without any issues at all. Just to clarify, I mentioned closed cell foam in my previous post. There are significant distinctions between closed and open cell foam.
That’s a brilliant idea! If water manages to get under the foam vapor barrier, it’ll function like a raft 😂
Why do you think it’s a terrible idea? Closed cell foam acts as a vapor retarder at 1.5″. Spraying it directly on the ground serves as both a vapor retarder and insulation, which is a win-win. It’s much easier and quicker to spray the CCSF in this space than to try to apply a 6mil poly with taped seams all over the ground and up the foundation wall.
If you’ve got that much water coming in under your house, it’s basically a flood and you’ve got bigger problems to tackle.
Can 1.5 foam support people crawling around and working on it? Just because it’s a vapor retarder doesn’t mean it’s waterproof.
Absolutely! 1.5 inches of CCSPF can easily support the weight of people walking and working on it.
That’s great!
I love sprinkling unicorn seeds on my oatmeal.
You fell for the hype without the engineering background to know better.
No one has used polyethylene as a soil vapor barrier since the 1980s. Technology has moved on in the past 45 years, but you can stick to your belief.
Once again, it’s never a good idea to insulate a floor. End of story. This was taught in the first few months of my 3-year Carpentry school training. And definitely not on a surface you can walk on!
We do retrofit crawlspaces as part of eneral Carpentry. Unfortunately, mice and rats are big fans of spray foam.
Then, there’s the whole world of permanent MCS ailments triggered and worsened by isocyanene off-gassing from spray foams. Once you have MCS, living in a regular home becomes impossible. You can’t even use most new fabrics or ride in cars. You end up in a specially-built room in an institution!
The IRC specifically includes polyethylene in the code as a Class I vapor retarder to be placed on exposed earth in crawl spaces. It’s also required under concrete slabs. And guess what meets the requirements? CCSF.
You never insulate floors? I’m not sure what you’re referring to…
I’m referring to the fundamental laws of thermodynamics that have been around for 450 years. It seems like you may not be familiar with them based on your response.
In Canada, our building codes take precedence over the IRC. While the IRC mentions polyethylene as a minimum requirement, it’s the last option on the list. Polyethylene is not used here due to its susceptibility to soil gasses. Remember, codes set the bare minimum standards, so when the IRC mentions poly, it means you should use it at least, not exclusively.
And yes, only inexperienced handymen would skip insulating floors. This information is not readily available online; you might need to consult a book or visit a library.
You can choose to build however you want, but what’s the purpose if you’re cutting corners?
Could you explain more about your decision not to insulate your floor? This is new to me.
Just so you know, I have a solid understanding of building codes and energy requirements. I’ve been teaching these topics for almost 20 years to various professionals in the industry. I’ve been working in construction since the late 1980s, focusing on high-performance homes, net zero homes, and energy-efficient homes. As a consultant, it’s crucial for me to stay updated on all these aspects.
What do you usually do with the exposed earth before installing the new subfloor?
Do you mind if I include your statement about only uneducated handymen insulating floors in my training sessions? By the way, have you checked out the Building America Solution Center website? It’s a great resource. They even showcase some Builder Challenge Homes from Canada in their case studies section, if I recall correctly.
I’m in the same boat as – entering my 36th year. If you’re struggling to come up with your own ideas, feel free to borrow someone else’s. That’s so typical of Americans, right? Can’t say I’m surprised. If you’ve got all that experience but still can’t see why insulating floors in homes is a waste of time and money, and goes against thermodynamics, then I’m afraid you’re headed for mediocrity, my friend. I’m calling bluff on your qualifications.
Seems to have exited the conversation… I was really hoping he’d explain why he thinks insulating floors is unnecessary.
Add receptacles where you don’t have them, and want them.
Add some cat5/cat6 wires to different walls.
Consider running conduit from this area to a place that can be accessed in the future for possible upgrades to computer cabling.
Do you need any water or drainage in this space, or on the exterior of the building? (Think about an outdoor kitchen or RV hook up on the outside of those walls)
Nice choice. Micro duct with a pull string, smooth bends
I would still include a service hatch in case a pipe breaks or animals start gnawing at any of the pex or Romex. Mice are particularly drawn to that material.
Fortunately there is no pex or pipe in hard-to-reach areas.
Basically, the entire right side is unreachable, but the left side and back are. That’s where all the piping is
Awesome.
Is there any plumbing work needed underneath the house?
Shawn Murphy lantschnig not at all!
When I re-sheetrocked my ceiling for surround sound and computer wiring, I wonder if it’s necessary in today’s Bluetooth world!
You know, I used to have a great Klipsch surround sound system, but we ended up removing it because it was too big and bulky.
Hey, I set up a Boston system in my den. It’s such a relief not having to worry about wire runs!
Are you referring to wifi? Wifi or bluetooth are options, but wired is much faster and more secure.
I like wired connections.
Do you offer this service to other people as well?
So, what are you thinking for furniture placement? I’d suggest adding some floor or wall outlets.
Ald Zaccaro what a fantastic suggestion! I should definitely install an outlet next to that pillar.
Doing this task is easy, especially if you’re thinking about setting up a surround sound system – get all the cables installed now!
Oh, definitely a time capsule! My child and I love hiding time capsules around the house. I bet in a hundred years, you could uncover a whole museum just by opening up the walls!
I’m not an expert, but my initial suggestion would be to consider some form of termite treatment for the wood.
Oh yeah, that copper liquid solution. I’ve always been curious why they don’t opt for pressure-treated lumber for all the sill plates near the ground. It might be quite costly, but I suppose it’s worth it in the long run to avoid termite damage.
Hey, this is what I was going to mention. It’s best to spray now to prevent any issues down the line.
Boric acid could also do the trick.
Exactly what they said! This is a great product for protecting wood from subterranean termites and drywood termites that can swarm in.
Do you have access to the area for pest control or other similar needs? If yes, I suggest creating enough space to easily move around, especially near your main HVAC duct, in case you need to make repairs or replacements in the future.
My main HVAC duct is easy to reach.
Hey ! But remember, that’s not the only reason you might need to go under the house. Removing dirt so you can crawl in if necessary is also a good idea.
Make sure to add conduit for pulling wires through.
Hey , that’s a great suggestion!
As someone who works in the telecommunications industry, I can confirm that ethernet and fiber optic cables are being installed deeper into homes to accommodate the increasing need for faster speeds. Coaxial cables just don’t make the cut anymore. This approach also helps reduce the need for unsightly track moulding or complicated installation processes.
Make sure to install access panels for anything you may need to access again. Additionally, if you live in a humid area, think about installing a permanent dehumidifier under the space. You won’t require a large unit for this.
Sounds great!
How about setting up a network of empty abs or pvc tubes to make it simple to run new ethernet and/or romex cables between rooms?
I’ve written numerous detailed solutions up here. Just do a quick search. Remember, never insulate a floor! Find out why.
I used to live in a post and pier home with a crawl space less than half a foot in some areas. I always thought about installing a misting system that emits Home Defense to keep critters away from under the house.
It seems like you have everything under control. ood job!
Perhaps you should consider installing a 3-inch pipe underground from one side to the other in case you need to run electrical wiring or something similar underneath 🤷♂️
Avoid using flex duct for HVAC if it’s installed under the subfloor.
Absolutely!
I’m wondering if this significantly impacts the flow?
Na Hartman yes, unless they are pulled very tightly, which is not the case for most. Metal ductwork reduces the risk of tears or damage from rodents, etc. Just my opinion, your experience may vary.
Mike alloway I currently have flex ducts under an additional subfloor with just a crawl space. I have consulted energy audit inspectors and 2 HVAC employees about the minimal heat flow in there.
Thank you for your response. Would it be best to switch to rigid ducts? Additionally, should they be suspended from the subfloor?
Na Hartman flex ducts have the potential to deteriorate and crack. It is recommended to use them in areas that are easily accessible for replacement if needed.
Na Hartman should consider using Aluma-Flex without any doubts.
I think this is the path that leads to the entrance of the crawl space.
Na Hartman, if you’re looking for durable ductwork, it’s best to use rigid material. Flexible ducts should only be used when necessary and kept as short as possible.
I wouldn’t recommend using flex in most cases. It’s a cheap and fast solution.
I’m on board with not using it, but I went with flex for my jump ducts to enhance the airflow in the bedrooms. Did it myself 😉
You might want to consider having a small trapdoor somewhere just in case. Just large enough for an average person to crawl under if necessary. You never know, it could come in handy.
A little tip: fill the crawl space with cat poop to deter other creatures from making it their home. You’ll thank me later.
Make sure to include a mock skeleton for the next person.
Would you mind digging a bit deeper to gain better access?
I completely agree, maybe even a foot deeper. Not sure if that’s doable considering the foundation though.
Not really into that idea, I’ve heard some horror stories about how it can mess with the foundation, etc.
Only if it was initially way off. @kara schindel is correct
Wow, looks like basements were definitely on the table during the construction of this house!
https://www..com/marketplace/item/7367765466635267/?mibextid=6ojiHh
Connect a gas line to the kitchen
If you have to install any electrical outlets, now is the moment.
Ducting should be Alumaflex when installing under the house.
Could you provide more information? Do you have a link or photo to share?
The level of insulation in your home can differ depending on where you live. Consult with your ducting/HVAC expert to determine the specific requirements. In my area, it’s R-8.
When planning for your HVAC system, make sure to account for the size of your home and the amount of air needed for each area.
I’m like my own expert in ducting, haha. Although R8 is the standard.
Air naturally follows the easiest route, so it’s not a one-size-fits-all situation.
Todd Jr. is awesome, the final outcome is always impressive. It’s especially satisfying when you tackle it on your own. Just remember to compare CFM with the size of the ducting.
We should also consider the impact of static pressure. I admire your determination to tackle this project independently, although it can be quite complex. Hopefully, you have connections in this field who can offer assistance.
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Consider adding joist hangers where beams do not connect above a support. Additionally, make sure to glue and screw your subfloor. If you live in an area with high radon levels, ensure the encapsulation is well sealed and set up a looping PVC manifold under the plastic sheet connected to a radon fan. This DIY project is fantastic for saving money. Well done!
https://www.youtube.com/watch?v=5nAgNpwHrxI
Have you thought about where you want to put your furniture? Are you planning to have the sofa against the wall? If not, you might want to consider adding a few floor outlets.
A new option is fiber optic for cable/internet. If possible, consider running conduit from where your utilities are located to the central point in your home where you plan to place the main device (router/modem).
My house is built on a slab, and neither AT&T nor Comcast will enter the attic anymore. They suggested running the new wire alongside the house, buried in my raised flowerbed, and drilling a hole through the house to run it along the wall. The only solution was for me to crawl through the attic trusses to the other end of the house, where the utilities are, and feed it through myself. It was a really unpleasant experience.
Ood for you doing it the right way! Those utility guys never seem to want to climb a ladder or go into an attic. I had a similar experience and ended up charging Comcast Xfinity. I explained how I wanted it done, the agent said it was fine, but the installer did it his way and laughed. After some complaints and showing them proof with pictures, they gave me a $250 credit. I even showed them what my billable time would be as a retired contractor and they paid half. It’s kind of funny. It only took me about 3 hours to reroute the cable from an old job.
I’m not sure that would work for me – even the “installer” was surprised by how determined I was. Honestly, he probably wouldn’t have fit…just saying. There isn’t much clearance, and I’m a pretty nimble woman.
Hey, I was actually thinking about suggesting the same thing. Maybe running some pvc or conduit to get those wires from point a to b?
Why isn’t that post, which is floating in midair, properly aligned with the brick piers?
Currently it’s being lifted by bottle jacks. Our next steps involve constructing a pier and then applying mortar.
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We need to grade or excavate 2 inches of stone, place a 6 mil poly vapor barrier, add a two-inch polyiso insulation board cut to size, another layer of 6 mil poly, and then pour two or three inches of concrete. Finally, we can rebuild the frame floor system on piers above this layer.
Make sure there is conduit running to each room.
I might take the time to remove some of the dirt. It can be useful to access certain areas. Maybe not every decade. But still worth considering. Especially if it serves a purpose.
Reat advice! Consider using cement pillars instead of blocks as they are more stable. Deeper cement pillars allow the ground to shift without affecting the building’s stability.
I was required to complete a $10,000 task 🫠
It won’t be too overwhelming if you handle it on your own.
I wasn’t prepared to handle that task and I’m also short on time.
Makes sense
That still seems really affordable. It comes out to around 7K when I handle it. That includes the floor and materials
I’ve been quoted over $20k multiple times. 🙃
Hey , it took a total of 3 days with 3 guys. They ended up replacing EVERYTHIN in the crawlspace
Hey , around 4 or 5 years back, it was likely nearly half of that…
I had slightly more space in the crawl space under my addition. I removed the floor to create enough room to crawl, then covered the ground with poly plastic and indoor-outdoor carpet to keep everything in place. My crawl space is unique with wall-to-wall carpeting, connected to a heated basement and located next to my wood-burning furnace, making it warm. I chose not to use a vapor barrier under the floor to allow any moisture to evaporate rather than getting trapped by plastic. No issues so far, and it’s convenient for maintenance work on ductwork, plumbing, or wiring.
Apply treatment to prevent termites
I’m currently doing the same thing. Trying to get rid of the old hardwood floors. I wanted to preserve them but it’s too difficult to remove and salvage. I’m not that patient.
Excavate a small space to crawl through
Consider using closed-cell spray foam for insulation. Additionally, install conduit pipes connecting accessible areas using 2″ PVC pipes (use straight shots and make slight bends when needed to avoid fittings, which can hinder wire installation later on).
Create a trap door on the side and excavate a tornado shelter or storage area below.
I once watched a man construct a cabin with a crawl space similar to this. He couldn’t reach underneath, so he attached 2×1 furring strips to the bottom of each joist to create makeshift shelves. After that, he placed plywood sheets on top of the strips to support rolled insulation and keep it elevated from the ground. This method allowed him to insulate the space and add a finished floor on top.