crawlspace

[Eric Smith]

Does everyone always call out a crawlspace that has a dirt floor with not plastic? I call it out and people are thinking I am nuts. Thanks.

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[Jim Robinson]

I think that would be a regional thing. People would definitely think I was nuts if I called it out here. It's pretty rare to see plastic in the crawl space in my area, but moisture in the crawl is pretty rare here as well.

[Jack Feldmann]

Its a big thing here in the south.

[Ted Menelly]

Its a big thing here in the south.

Hmmm

Is your state "In the South"

Just kidding. We know its not.

I do not think I have been in a crawl in the North Central Texas area that has had plastic on the ground or a sealed crawl and for that matter I think there has only been a couple with insulation.

[Scott Patterson]

Does everyone always call out a crawlspace that has a dirt floor with not plastic? I call it out and people are thinking I am nuts. Thanks.

You are not suppose to have exposed earth under a home.

Who is thinking you are nuts? If it is the Realtor or the Sellers then I would not worry about what they are thinking. Just report what you find.

A moisture barrier is important under a home, even if the area/ground is dry. Soil can look dry but you will find moisture once you dig down a little.

Now if you are in an aired area I don't think it is much of an issue. Last I looked IL is not very aired!!

[Rick Hurst]

I've been probably under a 1000 plus homes in the Dallas area and I've only seen maybe a dozen homes with a plastic barrier.

rick

[Bruce King]

In the south there is a rare situation that you have to watch out for.
This would be a crawlspace that happens to be dry with no vapor barrier and hardwood floors above it are really nice, tight and not buckled. If you recommend a vapor barrier, it gets installed, and the hardwood floors end up shrinking with gaps appearing, you just caused a problem.

Most of the time you need a 100 percent well overlapped vaopr barrier around here. Just did a 6 yr old house the other day that had zero vapor barrier with wood moisture 20-30 percent. Its a good thing the vents were open and the height above ground was much higher than typical or it would have been worse.

[Dom D'Agostino]

I've been probably under a 1000 plus homes in the Dallas area and I've only seen maybe a dozen homes with a plastic barrier.
rick

I'll go with "less than a dozen" in a 1000 homes.

Regional thing, I guess.

[Nick Ostrowski]

Does everyone always call out a crawlspace that has a dirt floor with not plastic? I call it out and people are thinking I am nuts. Thanks.

I do. Once you explain the rationale behind it and the way the exposed earth floor will allow a constant migration of moisture from the exposed soil into the basement area, people get it. Whether or not anybody actually follows my advice is another matter entirely.

[H.G. Watson, Sr.]

In most of central and northern illinois it would be nuts Not to have called it out.

[Zane Remenda]

Region thing sounds good to me.

I always recommend it. 100%

There is a lot of humidity here up north in the soil. (see enclosed pic)

Z

[Rick Bunzel]

In the Pacific Northwest it is a must have. Last spring 20% of the crawlspaces I went into had standing water. If the builder/installer bothered to run the plastic up the walls and overlap/tape the seams then most of the time the plastic kept the water out.

Unless you live in the desert, you want the moisture barrier.


//Rick

[Gary DeWitt]

In Southern California, plastic has not been used at all. This is not to say it would not be a good idea, about 5 percent of crawls I see are damp/wet. I think making assumptions based on the region you are in are dangerous.

Slightly off topic: water does conduct electricity quite well, and older houses frequently have exposed wiring. I will not crawl a generally damp/wet crawlspace and I note why on the report. Be careful out there.

[Jack Feldmann]

It is definitely a regional thing. When i lived in Long Beach, CA most of the crawlspaces were very dry. The ground was so dusty it was almost like talcum powder.
Here is East Tennessee, the ground is mostly clay and has a lot more moisture (probably because of the 50+" of rain per year.
Never saw vapor barriers in CA, in East TN, there are a must have.

[Scott Patterson]

A plastic moisture barrier also helps to keep out that earthy smell that can be present in homes without one.

[Jerry McCarthy]

So how many call out "rat proffing?"

[James Duffin]

I do but I call it "varmint proofing".

[Ted Menelly]

So how many call out "rat proffing?"

I do and the Realtors hate. Then they have to deal with it

[Jerry Peck]

So how many call out "rat proffing?"

I do but I call it "varmint proofing".

I call it as "rodent proofing".

[Nick Ostrowski]

How about calling it vermin and pestilence proofing?

[Jerry Peck]

I call it as "rodent proofing".

How about calling it vermin and pestilence proofing?

I use rodent proofing because various places in the code refers to rodents, such as:
- G2404.9 (301.14) Rodentproofing. Buildings or structures and the walls enclosing habitable or occupiable rooms and spaces in which persons live, sleep or work, or in which feed, food or foodstuffs are stored, prepared, processed, served or sold, shall be constructed to protect against the entry of rodents.

[John Kogel]

If it's a minor nuisance I use rodent, and if it's a serious invasion, I use Rat.

And yes, poly on the floor is essential here.

[Eric Barker]

So how do you make a home rat/rodent/varmint/critter proof? Resistant perhaps, but proof?

[Jerry Peck]

So how do you make a home rat/rodent/varmint/critter proof? Resistant perhaps, but proof?

Similar, but different, than doing "floodproofing" ... ain't nuttin' gonna work in a monster flood, but they still call it "floodproofing" ( FEMA: Floodproofing )

[Joseph Hagarty]

How about calling it vermin and pestilence proofing?

I identify it as vermin as well
Mouse, Rat, Squirrel, Raccoon, etc....

[Jerry Peck]

So how do you make a home rat/rodent/varmint/critter proof? Resistant perhaps, but proof?

Think of it this way - you "rodentproof" the house with rodent-resistant material (using the same terminology as in the code).

Kind of like "childproofing" a house by removing the easy-to-reach dangerous-to-the-child items, but that does not stop the child from getting a chair to stand on and reach those same items.

Another use would that you "waterproof" something, but it is only waterproof to a specified maximum depth.

[John Kogel]

I call it as "rodent proofing".

Jerry P, don't you know? In California, a 'rat prof' is a Rat Fink with a Phd.

I believe Billy S has a pic.

[Trent Tarter]

6 mil black plastic vapor barrier is required in my area. It's a standard recommendation where I live. As others have mentioned, it just depends on climate, location, and if it's required in your area.

[Jim Hintz]

Does everyone always call out a crawlspace that has a dirt floor with not plastic? I call it out and people are thinking I am nuts. Thanks.

Here's what can happen in a humid crawlspace due to no vapor barrier, poor ventilation and non-insulated heat ducting in a crawlspace.

[Ray Thornburg]

I used to work for a big builder around here who would but 20 yds of sand under every home......it made a real nice looking crawlspace. He would always say "sand is an approved vapor barrier" ....well I don't know about that statement but I was wondering if anybody has any comments about using sand in that manner to help control moisture under a home.

[Tom Rees]

Here is a link to some new thinking on crawlspace design: BSI-009: New Light In Crawlspaces — Building Science Information I believe I got it off this forum. In Utah we are very dry and as long as the crawlspace is well ventilated the plastic vapor barrier can do more harm than good. The only time (or most of the time) I see termites here is where there is a vapor barrier installed. The vapor barrier traps the moisture and provides perfect condition for termites. I do see the bare earth covered with gravel. The best ones actually have a slab poured. I think the crawlspace should be designed for individual conditions and not just generic one size fits all. Hope you all have a great Holiday season.

[Ted Menelly]

Here is a link to some new thinking on crawlspace design: BSI-009: New Light In Crawlspaces — Building Science Information I believe I got it off this forum. In Utah we are very dry and as long as the crawlspace is well ventilated the plastic vapor barrier can do more harm than good. The only time (or most of the time) I see termites here is where there is a vapor barrier installed. The vapor barrier traps the moisture and provides perfect condition for termites. I do see the bare earth covered with gravel. The best ones actually have a slab poured. I think the crawlspace should be designed for individual conditions and not just generic one size fits all. Hope you all have a great Holiday season.

I have been telling everyone that for years. Every home has its own conditions no matter what may be happening to the home next door. Unless a fortune is spent to turn crawl into a sealed crawl the right way then it has to be treated with what is gong on at the time. To just throw plastic on the dirt is not always a good idea at all.

As far as that sealed crawl. I am not sure I even like the idea in many cases. One minor drip of a water line or drain line and all that moisture is trapped in the crawl slowly rotting everything away and the occupants living in a very damp and musty home. We all know how often 99% of folks go into there crawl on a regular basis to check these things. Practically never.

For anyone to suggest that plastic be put into the crawl space and not to advise on further eval by the appropriate contractor in the area is asking for trouble in the future. Some folks may have mister handyman roll some plastic out causing all kinds of concerns

Don't just call out no plastic. If it is missing and you know for a fact that when the home was built and called for then advise for the further eval and repair.

[Door Guy]

I used to work for a big builder around here who would but 20 yds of sand under every home......it made a real nice looking crawlspace. He would always say "sand is an approved vapor barrier" ....well I don't know about that statement but I was wondering if anybody has any comments about using sand in that manner to help control moisture under a home.

The sand would help soak up some standing water until it gets saturated. Short answer is NO sand is not a vapor barrier.

[Tim Stolba]

I always recommend that a vapor barrier be placed over dirt floors in crawl spaces/basement. It is something that I just note in the report, not something that I would put on the summary unless there was an obvious mold issue.

[Eric Barker]

Ted, Around here I see too many damp crawl spaces due to absent barriers. This often leads to problems in the habitable and attic areas as well. Unless a crawl has indicators of a dry history I recommend a barrier be installed.

As for people not wanting to go into crawls - boy do I understand their reluctance! But ignoring a crawl space is just the same as ignoring any other system or component in the home. In my merciless view it's neglect.

If I ever did inspections down your way I'd be out of my element. I know what to expect up here in N. IL but elsewhere I'd have to study up on the region's peculiarities.

[Frank Norman]

If the crawl space is heated, e.g has some heating ducts running through it, then our code in BC requires a minimum 50mm concrete skim coat on top of the plastic. I don't know what the heating has to do with it, but I am guessing the rationale for requiring concrete is so that when folks use the space for storage, as they tend to do, the plastic is protected instead of it being torn, ripped, having sheets pulled apart etc., when boxes and whatever are thrown in or moved around in the crawl space. I have seen this and understand the need for the concrete skim coat over the plastic.

[Bill Boan]

.....Just did a 6 yr old house the other day that had zero vapor barrier with wood moisture 20-30 percent. Its a good thing the vents were open and the height above ground was much higher than typical or it would have been worse.

Bruce...just curious...how tall was the crawl? With moisture ranges above 20%, makers me wonder if the joists were laden with biological growth. And genuine hardwoods at 20-30%??? Saturation is generally at 25% and above---so were these floors buckled??? The way you say "coulda been worse".. leads me to believe they weren't. So did you recoomend vapor barrier in this case or not?

[Ted Menelly]

Ted, Around here I see too many damp crawl spaces due to absent barriers. This often leads to problems in the habitable and attic areas as well. Unless a crawl has indicators of a dry history I recommend a barrier be installed.

As for people not wanting to go into crawls - boy do I understand their reluctance! But ignoring a crawl space is just the same as ignoring any other system or component in the home. In my merciless view it's neglect.

If I ever did inspections down your way I'd be out of my element. I know what to expect up here in N. IL but elsewhere I'd have to study up on the region's peculiarities.

I am not disputing the fact that if anything is done correctly there will more than likely (but not always) be good results.

All I am saying is that every crawl has its own quirks, soil, moisture or even water in the crawl etc etc etc

If one were just to mention that plastic in the crawl was suppose to be there and leave it at that without further ado then it could and very well may cause more concerns than left alone. It has to be passed off to the pro for the area on crawl space .... let's say .... remodeling.

As far as folks going into the crawl of there home. I know folks that admitted (many folks) that they have never been in or looked in their crawl for 10, 20 years or more.

Now that could have created major problems ........ IF!

[Glenn Duxbury]

Hi, ALL &

Yessirree - never just dirt /soil (although there are many very old homes done that way)...

Poly (heavier the better), over rigid insulation & a concrete 'crust' laid-over is the modern standard.



Cheers !

[Caoimhín P. Connell]

Hello Erik –

My take is a little different. Plastic lining on an earthen crawlspace floor can create serious moisture problems in many structures. Oftentimes, the plastic has been installed by a “mould remediation� company (generally the least likely kind of company that has appropriate training in mould remediation).

In several cases, the plastic has resulted in significant mould growth in the crawlspace – in a number of properties, the corrective action was to remove the plastic and return the structure to a proper moisture balance.


Cheers!

CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Applications Consulting Technologies, Inc. - Home

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

[Door Guy]

Just goes to prove no two situations are exactly alike! Sometimes we try to put a blanket fix to all houses, each one is different!

[Raymond Wand]

Caoimhin the first paragraph describes what you refer to.


BSI-009: New Light In Crawlspaces — Building Science Information

[Caoimhín P. Connell]

Ach, well, Raymond… Doncha know, I taught Ol’ Joe everything he knows…

Cheers!

CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Applications Consulting Technologies, Inc. - Home

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

[Ted Menelly]

Hello Erik –

My take is a little different. Plastic lining on an earthen crawlspace floor can create serious moisture problems in many structures. Oftentimes, the plastic has been installed by a “mould remediation� company (generally the least likely kind of company that has appropriate training in mould remediation).

In several cases, the plastic has resulted in significant mould growth in the crawlspace – in a number of properties, the corrective action was to remove the plastic and return the structure to a proper moisture balance.


Cheers!

CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Applications Consulting Technologies, Inc. - Home

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

My fix for everything is .... windex. If it does not clean it it will cure it

More in line with the crawl and plastic, venting, not venting, insulation, no insulation.

I have said the exact same thing with every single post on here and everyone I have ever talked to.

It depends! On What? Way to many factors. If there is haevy moisture in the soil under the home you have to get rid of it in one way or another and the fix for it is not to just cover it with plastic.

Thanks for the contributing to you and Raymond.

I sound like a broken record on all these threads.

It depends on the particular crawl and home above it and how and where they were constructed etc etc etc.

[Jerry McCarthy]

In California it's commonly called "rat-proofing" although I would not argue against the terminology "rodent proofing."
Very common and most homes in urban areas have it, at least since the middle to late 50s.
It's God's way of punishing home inspectors, especially the ones that were formally builders who never bothered to smooth float the rat proofing before it set up.
(I be one of those)

[Darrel Hood]

Ted,
Your post implies that inspectors should have judgement. That will certainly upset the apple cart for the code quoters.

[Ted Menelly]

Ted,
Your post implies that inspectors should have judgement. That will certainly upset the apple cart for the code quoters.

My clients do not hire a robot. They hire me based on years of inspecting as well as being in the trenches. Why else would they hire an inspector. I am not sure why anyone would hire one of the mass amount of inspectors that just "learned the inspection process". No formal knowledge at all in the physics of a home.

Etc etc etc

[Don Hester]

Like many here in the more northern and damper regions vapor barriers are a must.

Here is our state (Washington) we have to call it out in a ventilated crawl. By the state standards this is a condition conducive to wood destroying insects and organisms.

And in any area where there is any suspected ground moisture you better recommend evaluation.

If you place plastic on the ground and see any condensation on the back of it you know you need it.

I am on the dry side of the state and see damage to homes with out vapor barriers.

Again one of the biggest issues is the over abundant use of fiberglass as an insulator. It performs poorly compared to other insulators (my opinion : ).

[Jon Patrick]

Wow.
First, I would think that whether you call out a plastic on the floor during an inspection would be partially dictated by your local codes... I live in NC so it's basically a necessity.

As far as that sealed crawl. I am not sure I even like the idea in many cases. One minor drip of a water line or drain line and all that moisture is trapped in the crawl slowly rotting everything away and the occupants living in a very damp and musty home.

argh. First, a properly installed Sealed Crawl will have a drain built into the poly to the low-point drain from the crawl - specifically for plumbing leaks. Further, it should be dehumidified by HVAC air or a dehum. There are FAR more crawls in my area 'rotting away' due to humidity from outside air than a minor leak in plumbing.
One crawl I saw was a multi-million dollar foreclosure that had been vacant for about 3 years. No dehum or hvac baffling, and no utilities for that time. standing water on the poly because the rear porch had been built over the band sill and was leaking water into the crawl.
About 16% moisture in the joists (except where saturated).

[Marc M]

man...I'd walk a mile for a plastic bottom crawl...