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What else should I consider doing while replacing the floor joists and subfloor in my 1940s farmhouse?

Asked by Fevrosiya Polovinko
6 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!

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Rosalyn Reyes

If you have any cast iron or copper plumbing underneath, consider upgrading to PVC or PEX pipes.

Rosalyn Reyes

Hey ! That’s fantastic news! Wishing you the best of luck.

Malou Hansen

Purchase a plastic skeleton and conceal it inside.

بیتا رضاییان

And randomly place a few empty beer cans nearby…

Titouan Girard

Haha…I was thinking the exact same thing…not that I would EVER admit to it..

Zoé Carpentier

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)

Zoé Carpentier

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.

Denise Dengler

Do you even know what a newspaper is? 😉

Abraham Fajardo

Rob Pepperidge Farm doesn’t forget, haha!

Zoé Carpentier

Okay, genius, just place a laptop with cnn.com open and bury it, or place it wherever you prefer

Denise Dengler

How on earth did you figure out I was a genius? I usually keep that a secret.

Zoé Carpentier

A genius would understand that was sarcasm

Abdellatif Mollen

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.

Daniel Valli

You may want to think about concealing any electrical, electronic, or other wiring.

Eren Bayındır

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.

Zoé Carpentier

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.

Denise Dengler

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.

Begüm Erginsoy

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?

Mirna Nikolić

Using small concrete pads for foundation blocks is a more efficient choice compared to using blocks or dirt.

Mirna Nikolić

Nicely done, having the right width is crucial, even though 2-3” might not be deep enough

Mirna Nikolić

Reat job, 👍

Dora Vujić

That’s what she remarked.

Seth Ford

Spray foam the exterior walls for added insulation and seal off with vapor barrier and rim box.

Evan Young

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.

Eemeli Waisanen

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.

Evan Young

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.

Tristan Mortensen

That’s a brilliant idea! If water manages to get under the foam vapor barrier, it’ll function like a raft 😂

Evan Young

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.

Evan Young

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.

Tristan Mortensen

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.

Evan Young

Absolutely! 1.5 inches of CCSPF can easily support the weight of people walking and working on it.

Eemeli Waisanen

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!

Evan Young

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…

Eemeli Waisanen

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?

Evan Young

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?

Evan Young

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.

Eemeli Waisanen

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.

Evan Young

Seems to have exited the conversation… I was really hoping he’d explain why he thinks insulating floors is unnecessary.

Isaiah Wilson

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)

Eléna Olivier

Nice choice. Micro duct with a pull string, smooth bends

Glen Rodriquez

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.

Glen Rodriquez

Awesome.

Dwayne Burton

Is there any plumbing work needed underneath the house?

Corinna Van Litsenburg

When I re-sheetrocked my ceiling for surround sound and computer wiring, I wonder if it’s necessary in today’s Bluetooth world!

Corinna Van Litsenburg

Hey, I set up a Boston system in my den. It’s such a relief not having to worry about wire runs!

Zoé Carpentier

Are you referring to wifi? Wifi or bluetooth are options, but wired is much faster and more secure.

Felix Mackay

I like wired connections.

Marina Pastor

Do you offer this service to other people as well?

Gopika Gamskar

So, what are you thinking for furniture placement? I’d suggest adding some floor or wall outlets.

Gopika Gamskar

Doing this task is easy, especially if you’re thinking about setting up a surround sound system – get all the cables installed now!

Renato Guevara

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!

Silke Poulsen

I’m not an expert, but my initial suggestion would be to consider some form of termite treatment for the wood.

Zoé Carpentier

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.

Felix Mackay

Hey, this is what I was going to mention. It’s best to spray now to prevent any issues down the line.

Marie Howell

Boric acid could also do the trick.

پارسا کامروا

Exactly what they said! This is a great product for protecting wood from subterranean termites and drywood termites that can swarm in.

Eren Bayındır

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.

Zoé Carpentier

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.

Filippa Olsen

Make sure to add conduit for pulling wires through.

Hannah Thomas

Hey , that’s a great suggestion!

Filippa Olsen

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.

Justin Frazier

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.

سپهر گلشن

Sounds great!

Zoé Carpentier

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?

Eemeli Waisanen

I’ve written numerous detailed solutions up here. Just do a quick search. Remember, never insulate a floor! Find out why.

Giray Kıraç

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.

Nora Falk

It seems like you have everything under control. ood job!

Obrad Živojinović

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 🤷‍♂️

Kristin Thomas

Avoid using flex duct for HVAC if it’s installed under the subfloor.

Tamara Vasić

Absolutely!

Esperanza Sanz

I’m wondering if this significantly impacts the flow?

Aurélien Masson

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.

Esperanza Sanz

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?

Kristin Thomas

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.

Angel Byrd

Na Hartman should consider using Aluma-Flex without any doubts.

Esperanza Sanz

I think this is the path that leads to the entrance of the crawl space.

Sohrab Eisses

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.

Clarisse Lecomte

I wouldn’t recommend using flex in most cases. It’s a cheap and fast solution.

Kristin Thomas

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 😉

Milica Đokanović

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.

Madeleine Jackson

A little tip: fill the crawl space with cat poop to deter other creatures from making it their home. You’ll thank me later.

Ambre Lecomte

Make sure to include a mock skeleton for the next person.

Kavitha Saha

Would you mind digging a bit deeper to gain better access?

Deniz Abacı

I completely agree, maybe even a foot deeper. Not sure if that’s doable considering the foundation though.

Arnaud Ouellet

Only if it was initially way off. @kara schindel is correct

Mathys Noel

Wow, looks like basements were definitely on the table during the construction of this house!

آدرینا كامياران

https://www..com/marketplace/item/7367765466635267/?mibextid=6ojiHh

Violeta Figueroa

Connect a gas line to the kitchen

Emilie Walker

If you have to install any electrical outlets, now is the moment.

Angel Byrd

Ducting should be Alumaflex when installing under the house.

Angel Byrd

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.

Angel Byrd

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.

Angel Byrd

Air naturally follows the easiest route, so it’s not a one-size-fits-all situation.

Angel Byrd

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.

Angel Byrd

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.

Angel Byrd

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Pierre-André Moulin

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!

Aurélien Masson
Iegor Nemolovskiy

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.

Iegor Nemolovskiy

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.

Glen Rodriquez

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.

Iegor Nemolovskiy

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.

Željko Stojaković

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?

Kostyantin Zasenko

Why isn’t that post, which is floating in midair, properly aligned with the brick piers?

Kostyantin Zasenko

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.

Teodor Vujčić

Make sure there is conduit running to each room.

Clarisse Lecomte

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.

Matteo Marchand

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.

Levon Hoftijzer

I was required to complete a $10,000 task 🫠

Jamie Lucas

It won’t be too overwhelming if you handle it on your own.

Levon Hoftijzer

I wasn’t prepared to handle that task and I’m also short on time.

Jamie Lucas

Makes sense

Levon Hoftijzer

I’ve been quoted over $20k multiple times. 🙃

Levon Hoftijzer

Hey , it took a total of 3 days with 3 guys. They ended up replacing EVERYTHIN in the crawlspace

Christian Suarez

Hey , around 4 or 5 years back, it was likely nearly half of that…

Sarah Vincent

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.

پرنیا صدر

Apply treatment to prevent termites

Jamie Lucas

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.

Carolyn Carlson

Excavate a small space to crawl through

Lilou Deschamps

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).

Charèl Vermaning

Create a trap door on the side and excavate a tornado shelter or storage area below.

Önal Denkel

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.

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