Crawl Spaces : Good vs Bad

Crawlspaces - The Good, The Bad, The UGLY, and how to build them BETTER!

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Huge thanks to our Show sponsors USG/Tremco, Polywall, Huber, Dorken Delta, Prosoco, Marvin Windows, Rockwool & Endura for helping to make these videos possible! These are all trusted companies that Matt has worked with for years and trusts their products in the homes he builds.

[thepinkerton]

I spent over 25 hours in my crawl after watching this the first time. Went from vented with roll bat underbelly, no sump and exterior access to sealed, conditioned, rigid foam perimeter, interior access and a sealed sump pit at each end. Watching again because noone else cares but us

[matt]

Matt...Most of the crawlspaces that I've ever seen, were in coastal communities in mapped flood zones where basements in these areas were prohibited, yet built prior to base flood elevation (BFE) standards being incorporated in the building codes. In certain communities here in the northeast, FEMA had recently completed flood map revisions, which placed existing homes with basements in a special flood hazard area (SFHA)...Those homes have lost significant value as the flood insurance premiums are cost prohibitive for most. The best recommendation for those facing this dilemma, is to move all of the mechanical systems, and fill their basements in to surrounding grade. That in itself will significantly reduce the flood premium, but not completely solve their issue as the (new) lowest floor elevation may still be under the BFE for that area. Flood insurance rates increase exponentially once a determined (by an elevation certificate) lowest floor elevation drops below the surrounding grade on all sides.

Many people would benefit from you posting a good tutorial on how to accomplish an affordable basement to a FEMA compliant crawlspace conversion.

[ForbiddenUser]

I used to have a really nasty crawl space under my house... That is until my street's sewer line backed up, and back pressure forced the entire street's sewage into it once it popped the main line off. I couldn't even get a plumber to go down there to repair the broken pipe until I had a restoration company come in, which is basically a hazmat team to clean up the mess. What they did in the process was basically totally modernize my crawlspace, installed a vapor barrier, put down clean fresh sand to replace all the contaminated debris they removed. The best part was because it was caused by a blockage in the city's lines, they footed the bill for the entire process. Almost 10k$ between the restoration and the plumbing bills, and now I've got a beautiful crawlspace that makes it a dream to get down in when working on plumbing and what not. I've never been so happy over a sewage backup before.

[johnlimongello]

I was a home inspector for 5 years in Georgia... Heard a story from an old-timer that actually found a human skeleton in a crawl space. He had to leave immediately and called the police... Turns out they buried grandma in the crawl space because they couldn't afford a funeral.
Thanks for the video... I appreciate the info and totally agree that crawl space should be conditioned spaces.

[seanm]

The one takeaway from this video...is that money is no object.

[SearTrip]

Not a builder, just a homeowner. I had just changed my dehumidifier filter in my crawlspace when I came back up to you having posted this video. I’d been worried about it for a while, and this video was the straw that broke the camel’s back and got me moving. We had most of the problems you talked about. We found a company that encapsulates existing crawl spaces in our area. They just finished today. Not the most sexy space to spend money in the house, but I feel much happier about the sealed, drained, encapsulated area under the house now.

[phildnyc]

I bought a house in upstate NY with a crawl space - its dry with concrete floor and cinder walls, insulated with spray foam under 1st floor but still has a few vents - not perfect (yet) but not wet and not cold. Since its my first house and haven't seen many crawl spaces before, I wasn't sure of quality of the space so its helpful to get a frame of reference for what is good and what to avoid or fix. Really helpful video.

[stringsandapick]

I love retrofitting old crawlspaces with closed cell foam and vapor barriers. Massive benefits in efficience and air quality.

[volundrfrey]

I've been in a crawl space here in Scandinavia in a house that was build the year 1900. It was great. It was well ventilated and the ground drained well. No plastic to trap water, so very little rot or bad odours even after 100+ years. The entire house was just extremely well built and throughout.

[JohnVance]

This is so timely for me! I've got an old house with a really terrible crawlspace. Have been looking at encapsulation or maybe even a full dig-out. I love the drop-down ladder! It's like attic stairs in reverse.

[TravelAboveMe]

I'm an engineer by degree and an industrial project manager by profession, and have been eager to get into home construction for awhile. As a segue into the field, I purchased an 1920's home a year ago and have been renovating it solo with immense study of codes and best practice, a lot of which comes from Matt's video's. It really makes me wish my early years were spent training under someone like Matt who clearly knows plenty of the tried and true methods, but is happy to entertain the up and coming technologies as well. I love the videos and appreciate the time put into making them - this is an excellent channel!

[sirwilliam]

You just gave me a great education on a property that I'm considering.
It has some serious moisture damage from accumulated time and probably venting down in Louisiana. I'm having an inspector go down and look at the damage to see if the entire floor joists need replacing or just several along with the subfloor. You convinced me to get that dried out, replace the damage and seal up the foundation to make it a place for my grandson to inherit.

[kennieloo]

I’ve watched this video before but it just didn’t click. Glad this resource is always here. Thanks a ton!

[nsuddeth]

Absolutely love this video! One of my primary resources for learning home improvement methods is This Old House. However, I've learned by now that crawlspaces are apparently non existent in the New England area and thus they virtually NEVER have episodes pertaining to crawlspaces. Thanks for making this video, nice to get some valuable info. You've given me a lot to research further now.

[MoneyPitCastle]

Whenever I'm looking for a video on any subject, Matt akways has one. Thanks for this

[jonz]

I live in southern BC, right on the WA border. Climate Zone 4. The 3' high crawl space in my 25 yr. old home has poured concrete slab and walls. The walls are always dry but there are lots of damp spots on the floor (no puddled water), a fair bit of efflorescence and some mold spots. There are no rodents or termites. The perimeter drain pipes are fine - I have them inspected/cleaned every 5 yrs. The heating system is forced air so I had the furnace guys cut vents in the supply and return air ducts a few years ago. After tons of research, I am DIY'ing a clean-up with Concrobium, and then sealing the concrete with a chrystalline sealer like Xypex High'N Dry. My question is about the rigid board insulation for the walls. I'll probably use R10 but I can't get a consistent answer on whether I need it to be foil-faced. I'd appreciate your opinion on my plans and on the insulation. Thanks! Jon

[rodneyhammon]

You definitely have the best home building show around!…I’ll be moving to Florida in 2021...and I have so many notes and tips on new construction from this channel...I’m so very grateful for all your hard work on these videos, which in turn will help me when I have
my home built!…thank you!...

[stevepark]

You didn't mention anything about air movement in a sealed or conditioned crawl space. I do believe a sealed crawl space is the way to go, I have completely sealed my crawl space and it is fantastic, (no shoes in my crawl space, Lol), but also it is now part of the air of the entire house, so part of the heating and cooling system. without air movement you can have moisture build up? Yes? or adding a dehumidifier in the crawl space to regulate the humidity. Love your input, Thanks for the video.

[Babarudra]

looking at a house with a crawlspace. I haven't been in it yet, but trying to get some preemptive information on how to make it better. I doubt much has been done to make it good. It was built in 1890, so who knows what I'll find. This was the first video of yours I've seen that deals with crawlspaces, I'm hoping that there's more. I'll be rewatching your attic videos too. Thanks for always having great information.

[eliinthewolverinestate]

Have you ever taken a close cell foam float out to the lake? They do become water logged. If you have closed cell foam up against a sealed masonry foundation it can become water logged. Masonry needs some above ground area to dry out. Just saying. Rockwool up against masonry is a better choice. To allow things to breath. Are roof vent baffles required by code down south? After I finish supporting my old house in the crawl space. I will be rolling out some vapor barrier. Tempted to spray foam that brick along outside wall in the crawl space after a lime white wash.