Fresh air intake and radon

[Scioto78]

New member. Built a new house a few years ago and my wood stove is in the basement, which the whole backside of the house is walkout with windows. Stove is centrally located and chimney goes up through the center of the house, which is a single level home, fairly high pitched roof. Have always had tremendous draft from day one. I’m a believer in radon gas and how it is emitted through the ground. I built in a radon fan pipe that is underneath my basement slab and it has a fan that runs 24/7. I have a digital radon detector in the basement and check it periodically. Something I’ve noticed is when the wood stove is revved up, my radon level goes up. Fresh air intake is a debate for me because it appears the stove is creating a negative pressure and pulling the radon through any cracks and into the room. Debating about installing a fresh air intake for my stove, but not sure if about bringing in cold air for this. Any thoughts on this or suggestions?

 

[bholler]

New member. Built a new house a few years ago and my wood stove is in the basement, which the whole backside of the house is walkout with windows. Stove is centrally located and chimney goes up through the center of the house, which is a single level home, fairly high pitched roof. Have always had tremendous draft from day one. I’m a believer in radon gas and how it is emitted through the ground. I built in a radon fan pipe that is underneath my basement slab and it has a fan that runs 24/7. I have a digital radon detector in the basement and check it periodically. Something I’ve noticed is when the wood stove is revved up, my radon level goes up. Fresh air intake is a debate for me because it appears the stove is creating a negative pressure and pulling the radon through any cracks and into the room. Debating about installing a fresh air intake for my stove, but not sure if about bringing in cold air for this. Any thoughts on this or suggestions?

Not sure why you are debating it just install an outside air kit

 

[Gearhead660]

New houses are very air tight. I would install an OAK.

 

[EbS-P]

When you say goes up how much are you taking about. Running a shower makes it for up but depending on your water source it can go up a completely insignificant amount or enough that you would not want to spend all day in the bathroom with the shower running.
Evan

 

[aansorge]

Other than extra work, their really isn't a downside to an OAK that I can think of. It sucks in cold air but that goes into your stove, not the rest of your house. If you don't have one, you get negative pressure in your house that creates an air draw of cold air throughout your house.

 

[Das Jugghead]

New member. Built a new house a few years ago and my wood stove is in the basement, which the whole backside of the house is walkout with windows. Stove is centrally located and chimney goes up through the center of the house, which is a single level home, fairly high pitched roof. Have always had tremendous draft from day one. I’m a believer in radon gas and how it is emitted through the ground. I built in a radon fan pipe that is underneath my basement slab and it has a fan that runs 24/7. I have a digital radon detector in the basement and check it periodically. Something I’ve noticed is when the wood stove is revved up, my radon level goes up. Fresh air intake is a debate for me because it appears the stove is creating a negative pressure and pulling the radon through any cracks and into the room. Debating about installing a fresh air intake for my stove, but not sure if about bringing in cold air for this. Any thoughts on this or suggestions?

Properly done an OAK will not bring any cold air into the house - to the contrary it actually slows cold outside air from infiltrating through the building envelope itself thereby helping to keep your house warmer. I have a somewhat similar situation in that we have a small stove with a tall (28') flue that drafts like a jet engine. I built an OAK for my stove at the end of the summer and it made a tremendous difference in the comfort level in our home. We also have a radon mitigation system that draws from our sump pit and it runs 24/7.

Pleasant Hearth WS 2417 Outside Air Intake Build

At the end of 2018 I purchased a Pleasant Hearth WS-2417 woodstove. That installation and subsequent learning process is described here: https://www.hearth.com/talk/threads/pleasant-hearth-ws-2417-install-challenges-questions-observations.173074/ Several issues have been on the list to...

www.hearth.com

What wood stove do you have?

 

[Scioto78]

Properly done an OAK will not bring any cold air into the house - to the contrary it actually slows cold outside air from infiltrating through the building envelope itself thereby helping to keep your house warmer. I have a somewhat similar situation in that we have a small stove with a tall (28') flue that drafts like a jet engine. I built an OAK for my stove at the end of the summer and it made a tremendous difference in the comfort level in our home. We also have a radon mitigation system that draws from our sump pit and it runs 24/7.

Pleasant Hearth WS 2417 Outside Air Intake Build

At the end of 2018 I purchased a Pleasant Hearth WS-2417 woodstove. That installation and subsequent learning process is described here: https://www.hearth.com/talk/threads/pleasant-hearth-ws-2417-install-challenges-questions-observations.173074/ Several issues have been on the list to...

www.hearth.com

What wood stove do you have?

Interesting. My stove is a US Stove 3000/ Country Hearth. I’ll probably plan on installing an OAK before next season. Looks like there’s a 2” air intake pipe on the back bottom of my stove. Does that mean you take 2” all the way outside, or step it up to 3” or so to go outside? And did. You insulate yours to keep the cold air from condensing? Thanks

 

[Scioto78]

Other than extra work, their really isn't a downside to an OAK that I can think of. It sucks in cold air but that goes into your stove, not the rest of your house. If you don't have one, you get negative pressure in your house that creates an air draw of cold air throughout your house.

Totally makes sense and probably why the radon level shoots up typically when the stove is going good. I’ll plan to install one before next burning season. Thanks

 

[Scioto78]

Thanks for the replies. I’ll plan to install an air intake before next burning season for sure.

 

[Scioto78]

When you say goes up how much are you taking about. Running a shower makes it for up but depending on your water source it can go up a completely insignificant amount or enough that you would not want to spend all day in the bathroom with the shower running.
Evan

Rainy periods has traditionally made it go up. Highest it’s been since the mitigation fan was installed is around 4.0. Typically averages 2.0-3.0 during the winter...

 

[EbS-P]

Any explanation as to why rain increases radon levels?

 

[moresnow]

Any explanation as to why rain increases radon levels?

Sump pit cycling perhaps?

 

[Scioto78]

Always has increased on heavy rain periods. Assuming the heavy rain pushes the gas out of the ground? No sump in the basement, it’s a walkout with gravity drain and French drain to daylight. Basement is dry.

 

[avsmusic1]

what's threshold/rating is deemed hazardous?

 

[NewStoveOwner2020]

Any explanation as to why rain increases radon levels?

Radon escapes from the ground upward. When snow and rain saturate the earth around the house radon comes up through the house. Prior to mitigation we say changes of 200bqm-500bqm a number of hours after heavy rain.

To the original poster.
We had a stove installed in our home 2 months ago and the installer did not detect any draft with the radon kit installed. Stove in the basement, chimney through the main floor and the attic, where it enters the attic we had a strong strong draft I insulated it as per the instructions given to me by the installer and since then we have had a bad bad draft.

Installed a OAK fires ran hotter but still the draft made it smell like 'fireplace' in the AM when it cooled.

Called the radon guy and he replaced the fan with a lower CFM one , reconducted the assessment and deemed the sub slab pressure to be adequate with a smaller fan and the draft is nearly gone.

The only way I was able to 100% remove the draft was to open the window a crack (not ideal) or what I have been doing is leaving the 4inch dryer venting unplugged and air comes in through there across the room very slowly. This causes significantly less negative pressure in the basement.

Our plan will likely be to vent the dryer (not gas) into the house as with the wood stove the RH is 27% and we do laundry every 3 weeks and air dry most our stuff. In the summer I'll hook it back up as the wood stove is not in use. No extra holes in my house bringing in moisture required.

The basement is unfinished insulated, house built in 2018.
Not sure if the above information helps you but I may spark some ideas on how to deal with having a radon kit and a wood stove in the same space. Just the radon kit was 'ok' but turn on the dryer (when vented outside) or the bathroom fan and you get smoke in the house. I know new houses are meant to be sealed well but I was not a fan of adding a big hole year round to solve a problem I would have for half the year.

Since allowing more air into the basement my main floor actually gets heated passively from the stove. Before every fan and lock had air being pulled backwards from the main floor into the basement and running the stove 'cooled upstairs' without minimal heat rise.

 

[Das Jugghead]

Interesting. My stove is a US Stove 3000/ Country Hearth. I’ll probably plan on installing an OAK before next season. Looks like there’s a 2” air intake pipe on the back bottom of my stove. Does that mean you take 2” all the way outside, or step it up to 3” or so to go outside? And did. You insulate yours to keep the cold air from condensing? Thanks

I ran the same size piping but my setup is a little different from yours. It sounds like your stove drafts hard enough that the size of the piping for the OAK isn't that much of a difference for the sizes you referenced. I would, however, suggest you consider downsizing the Diameter of the piping to try and slow down your burns - it worked for me as referenced in my OAK build thread.

I did insulate my intake primarily where it entered the building.

 

[Scioto78]

I ran the same size piping but my setup is a little different from yours. It sounds like your stove drafts hard enough that the size of the piping for the OAK isn't that much of a difference for the sizes you referenced. I would, however, suggest you consider downsizing the Diameter of the piping to try and slow down your burns - it worked for me as referenced in my OAK build thread.

I did insulate my intake primarily where it entered the building.

Thanks

 

[Scioto78]

Radon escapes from the ground upward. When snow and rain saturate the earth around the house radon comes up through the house. Prior to mitigation we say changes of 200bqm-500bqm a number of hours after heavy rain.

To the original poster.
We had a stove installed in our home 2 months ago and the installer did not detect any draft with the radon kit installed. Stove in the basement, chimney through the main floor and the attic, where it enters the attic we had a strong strong draft I insulated it as per the instructions given to me by the installer and since then we have had a bad bad draft.

Installed a OAK fires ran hotter but still the draft made it smell like 'fireplace' in the AM when it cooled.

Called the radon guy and he replaced the fan with a lower CFM one , reconducted the assessment and deemed the sub slab pressure to be adequate with a smaller fan and the draft is nearly gone.

The only way I was able to 100% remove the draft was to open the window a crack (not ideal) or what I have been doing is leaving the 4inch dryer venting unplugged and air comes in through there across the room very slowly. This causes significantly less negative pressure in the basement.

Our plan will likely be to vent the dryer (not gas) into the house as with the wood stove the RH is 27% and we do laundry every 3 weeks and air dry most our stuff. In the summer I'll hook it back up as the wood stove is not in use. No extra holes in my house bringing in moisture required.

The basement is unfinished insulated, house built in 2018.
Not sure if the above information helps you but I may spark some ideas on how to deal with having a radon kit and a wood stove in the same space. Just the radon kit was 'ok' but turn on the dryer (when vented outside) or the bathroom fan and you get smoke in the house. I know new houses are meant to be sealed well but I was not a fan of adding a big hole year round to solve a problem I would have for half the year.

Since allowing more air into the basement my main floor actually gets heated passively from the stove. Before every fan and lock had air being pulled backwards from the main floor into the basement and running the stove 'cooled upstairs' without minimal heat rise.

Yes, good info and thanks for the reply. Regarding smell, I have never had any “fireplace” smell in the basement or house, which, growing up with a stove in the basement, I kind of miss having a little bit of smell, but... I can even leave my wood stove door open and nothing, so drafting even with all the doors and windows shut in the 2017 built home, dryer running, radon fan running, is great. .. the basement is a full walkout on the back with 3 large, 6x6 windows and a set of double doors, so blind to be a minimal amount of air leakage there, plus there’s an abandoned dryer vent stuffed with insulation on one end of the house where I changed my mind where I was going to vent... stove passively heats the upstairs great. All concrete walls in the basement at the moment, but would like to stud up and insulate, which I’m sure would make a difference as far as heat loss in the winter... Stove is centrally located in the basement and chimney is a mason block with the 7” 16 gauge single wall flue with vermiculite poured in around it the whole way up (but some of that has leaked a little through the flue joints over time, but no way to remedy unless I reline the flue and caulk each joint. Problem is that vermiculite is sometimes so fine, that there’s no way to stop it from leaking until it gets to a certain point. It’s probably leaked down enough where it’s level with my roof line and not all the way to the top anymore, but, good enough I guess). Chimney goes up and is exposed in my laundry room, which puts off good heat there as well once it’s warmed up. Overall, very happy with the setup. Wondering if putting a valve in the oak in case I would want to just pull in inside air again ? Thanks