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I recently had the opportunity to have an inspector from SC come to Raleigh to do an inspection for me. My buyer is his daughter.
I asked him the above question.
His answer was...if you are NOT having problems with moisture and you have a vapor barrier (100% vapor barrier is good), then you should keep them open unless you have a few days of freezing weather. If the weather is freezing, you should close them.
I agree with the above poster...the vents are there for a reason.
Foundation vents are installed to provide air circulation and allow moisture/dampness in the crawl space to escape......if you keep them closed your defeating the purpose for which they were installed.....your also preventing radon from escaping which will then penetrate into your living area above.....keep your crawl space vents open !!!
Would you mind posting your credentials and certifications for us. This way we can compare them with Sacred's and be able to make a better informed evaluation of the thoughts.
Would you mind posting your credentials and certifications for us. This way we can compare them with Sacred's and be able to make a better informed evaluation of the thoughts.
He really knows his stuff about radon as we have talked (or argued lol) in the past. The difference with our region is humidity is a MUCH larger problem than radon gas. The humidity is guaranteed to have a high level while radon is really hit and miss, and even the readings that come back high are typically still in the single digits. In certain neighborhoods it would be a concern, but overall it is not. This is also easily remedied with a foundation vent fan on one side and leaving a couple vents opened on the other. In that case, an installed dehumidifier takes care of any humidity that enters through the couple opened vents. Air exchange in a crawlspace using only the vents is tremendously slow. Even on a windy day there is virtually no breeze in a crawlspace. The pressure differentiation is the reason for this and without using a mechanical device to pull/push the air around you have the slow exchange.
There is a push to eliminate foundation vents from our code as we speak....and not just because I am a proponent. It has been well studied by people much smarter than I am.
My line of thinking is still in the minority, basically because people stick to the conventional wisdom and are slow to come around. It is a significantly growing minority though and after myself and countless others observing thousands of crawlspaces, seeing the effects, and implementing solutions that work, the results have proved the theory. I do believe fully sealed crawlspaces are overkill and unwarranted in almost every case, but basic moisture control measures that greatly improve upon a passive vent system make for a nice preventative.
He really knows his stuff about radon as we have talked (or argued lol) in the past. The difference with our region is humidity is a MUCH larger problem than radon gas. The humidity is guaranteed to have a high level while radon is really hit and miss, and even the readings that come back high are typically still in the single digits. In certain neighborhoods it would be a concern, but overall it is not. This is also easily remedied with a foundation vent fan on one side and leaving a couple vents opened on the other. In that case, an installed dehumidifier takes care of any humidity that enters through the couple opened vents. Air exchange in a crawlspace using only the vents is tremendously slow. Even on a windy day there is virtually no breeze in a crawlspace. The pressure differentiation is the reason for this and without using a mechanical device to pull/push the air around you have the slow exchange.
There is a push to eliminate foundation vents from our code as we speak....and not just because I am a proponent. It has been well studied by people much smarter than I am.
My line of thinking is still in the minority, basically because people stick to the conventional wisdom and are slow to come around. It is a significantly growing minority though and after myself and countless others observing thousands of crawlspaces, seeing the effects, and implementing solutions that work, the results have proved the theory. I do believe fully sealed crawlspaces are overkill and unwarranted in almost every case, but basic moisture control measures that greatly improve upon a passive vent system make for a nice preventative.
You gave the best answer in a previous discussion. After awhile it boiled down to a couple of points that made multiple perspectives right. I believe part of if was if you have been living in the house and have no problem you could continue what you are currently doing.
You gave the best answer in a previous discussion. After awhile it boiled down to a couple of points that made multiple perspectives right. I believe part of if was if you have been living in the house and have no problem you could continue what you are currently doing.
Exactly right! Just thought I would expound on the reasoning for moisture controls a bit there lol.
Would you mind posting your credentials and certifications for us. This way we can compare them with Sacred's and be able to make a better informed evaluation of the thoughts.
I was a prepurchase home inspector for 20 years doing over 5000 home inspections but switched about 5 years ago from doing home inspections and radon testing/mitigation to move into radon full time. Currently I am and have been a New Jersey DEP certified/licensed radon specialist with 20+ years experience......I do some testing but mostly I mitigate homes with excessive levels......about 150 homes a year.
I was a prepurchase home inspector for 20 years doing over 5000 home inspections but switched about 5 years ago from doing home inspections and radon testing/mitigation to move into radon full time. Currently I am and have been a New Jersey DEP certified/licensed radon specialist with 20+ years experience......I do some testing but mostly I mitigate homes with excessive levels......about 150 homes a year.
Excellent now knowing that the discussion between you and Grooves becomes especially enlightening. Sorta brings me to a semi conclusion the last time this topic went around. There is expert opinion on both sides of the issue and most of us in the middle are better off if we make our decision based on your thoughts and not urban wisdom. We reached the point before that either can be right based on your individual circumstances and not all houses and crawl space heights are the same. If you plant shrubs around your house and block the vents you are minimizing the benefits of leaving them open. Also we got into the impact of the slope around your house and natural drainage etc etc etc. I am really glad to read your background and what you said. When I sold my house up north I had to have radon abatement done by a guru in your field. He gave me a detailed most current study about crawlspaces and the vents. It got buried in the move but I thought for sure it said leave them open year round and when I mentioned that in the previous discussion I thought I must have remembered it wrong. However now your posting and background seems to suggest I remembered it correctly. Thus I am back to where I was after the last go round. It appears that it is very much situational and each individual needs to evaluate theirs with the knowledge of experts like you and Grooves.
Excellent now knowing that the discussion between you and Grooves becomes especially enlightening. Sorta brings me to a semi conclusion the last time this topic went around. There is expert opinion on both sides of the issue and most of us in the middle are better off if we make our decision based on your thoughts and not urban wisdom. We reached the point before that either can be right based on your individual circumstances and not all houses and crawl space heights are the same. If you plant shrubs around your house and block the vents you are minimizing the benefits of leaving them open. Also we got into the impact of the slope around your house and natural drainage etc etc etc. I am really glad to read your background and what you said. When I sold my house up north I had to have radon abatement done by a guru in your field. He gave me a detailed most current study about crawlspaces and the vents. It got buried in the move but I thought for sure it said leave them open year round and when I mentioned that in the previous discussion I thought I must have remembered it wrong. However now your posting and background seems to suggest I remembered it correctly. Thus I am back to where I was after the last go round. It appears that it is very much situational and each individual needs to evaluate theirs with the knowledge of experts like you and Grooves.
The best I can offer on ventilation is that I have never seen an expert recommend against whether it be a crawl space or an attic......too much humidity, condensation, etc will only lead to rot or deterioration in some form. While a plastic sheeting vapor barrier spread over a dirt crawl space floor to help reduce moisture concerns is certainly recommended its only one step in the process of eliminating moisture concerns......cross ventilation from open foundation vents is also recommended to give moisture and humidity a place to escape.....with no place to escape your framing will eventually rot from exposure to excess dampness and you run an increased risk of attracting termites who love dampness, exposed wood and dark places.
Me too. I guess it's the Realtor mentality. We think alike. I wonder what Mike and Leigh do!!!
I pick between hockey and basketball. All winter.
Most of my vents are open, and I leave them alone.
Have a little black mold spore under the house, and that is about it.
I do get some condensation off the ductwork in the summer, and it pools in a couple of spots on the vapor barrier.
I worry more about controlling ground water against my foundation, downspouts and all.
I think the concerns about mold will lead us to more and more slab foundations, where applicable.
Damper lots in my subdivision have slabs.
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