# To seal or not to seal



## SeniorSitizen (Sep 10, 2012)

You've seen what the poly can do so now the next move is to quit using those chinese gemmickie measuring instruments and get a real humidity reading by using dew point temperature. The walls reaching dew point temperature behind the poly is probably what caused the moisture problem there.


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## sonnaps (Jul 21, 2015)

SeniorSitizen said:


> You've seen what the poly can do so now the next move is to quit using those chinese gemmickie measuring instruments and get a real humidity reading by using dew point temperature. The walls reaching dew point temperature behind the poly is probably what caused the moisture problem there.


Hi there, can you link to something that I can read into? I am not familiar with that. When I first pulled off the wood paneling I did see a lot of condensation on the poly before I ripped that off too. Do you think I have to do anything other than new poly on the walls and leveler on the floor with tile right over?


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## SeniorSitizen (Sep 10, 2012)

sonnaps said:


> Hi there, can you link to something that I can read into? I am not familiar with that. When I first pulled off the wood paneling I did see a lot of condensation on the poly before I ripped that off too. Do you think I have to do anything other than new poly on the walls and leveler on the floor with tile right over?


Evidently you don't see a problem with condensation on the poly you ripped off. If that's true I can't help you. Sorry


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## sonnaps (Jul 21, 2015)

SeniorSitizen said:


> Evidently you don't see a problem with condensation on the poly you ripped off. If that's true I can't help you. Sorry


Lol, no I get what you mean. The original poly is what caused the staining in the first place, I agree. I just wonder why my readings are what they are. Some blocks show 0% moisture levels and some 30% or even higher. If my moisture meter is a piece of crap and is just me wasting my time, then how would I go about getting a real humidity reading by using dew point temperature? Using something like this?

http://andrew.rsmas.miami.edu/bmcnoldy/Humidity.html

I would type the outside temperature and relative humidity in the house from my little weather station thing and then I would get the dewpoint? If the inside house temperature reached down to that result, I would get condensation on the poly if it was on?


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## stadry (Jun 20, 2009)

any sealing should be done outside, not inside,,, once that's done, start running a dehumidifier


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## sonnaps (Jul 21, 2015)

stadry said:


> any sealing should be done outside, not inside,,, once that's done, start running a dehumidifier


What about the concrete slab though? I'm looking into dehumidifiers right now actually.


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## Canarywood1 (May 5, 2012)

If it were mine i'd use a water repellent outside instead of a sealer, as to the slab there's probably no vapor barrier, the slab is wicking the moisture up from the ground, sealer won't do any good there and may prevent a bond if you intend to top it with something.


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## Yodaman (Mar 9, 2015)

The only product I would dare to use on the inside walls is Thoroseal. It is a permeable coating that will allow the wall to dry. Not exactly a decorator type finish, but it will preserve the integrity of the block and mortar.


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## Canarywood1 (May 5, 2012)

And i wouldn't even use that until the water repellent was applied and the humidifier was running for a few weeks or so,


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## SeniorSitizen (Sep 10, 2012)

sonnaps said:


> Lol, no I get what you mean. The original poly is what caused the staining in the first place, I agree. I just wonder why my readings are what they are. Some blocks show 0% moisture levels and some 30% or even higher. If my moisture meter is a piece of crap and is just me wasting my time, then how would I go about getting a real humidity reading by using dew point temperature? Using something like this?
> 
> http://andrew.rsmas.miami.edu/bmcnoldy/Humidity.html
> 
> I would type the outside temperature and relative humidity in the house from my little weather station thing and then I would get the dewpoint? If the inside house temperature reached down to that result, I would get condensation on the poly if it was on?


First of all condensation / moisture problems usually doen't happen in the summer months but in colder months. That's why dew point temperatures need to be monitored in cold times of the year to obtain information as to when structure components such as your walls and floors are at risk of condensing moisture on their surfaces the same as moisture would appear on a iced tea glass.

If your house is un-occupied and not conditioned ( cooled or heated ) you can use the National Weather Service information by entering your zip ( upper left )and it will give the info. nearest you. Temp., dew point temperature and relative humidity updated it seems like maybe each hour. If / when you condition the house that changes the whole ball game and you must take your own readings.

http://forecast.weather.gov/MapClic...6.94024576642823&site=all&smap=1#.VbF8W_m5W1s

You can use the link you provided to calculate dew point if you had an accurate reliable relative humidity instrument. Being I don't have a reliable RH instrument I use dew point temperature to calculate RH. 

I do have an accurate means of measuring DP but the method has been shunned on this site so much I'll not mention it in this discussion. I think my information is set to receive private messages though.


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## sonnaps (Jul 21, 2015)

Yodaman said:


> The only product I would dare to use on the inside walls is Thoroseal. It is a permeable coating that will allow the wall to dry. Not exactly a decorator type finish, but it will preserve the integrity of the block and mortar.


So maybe my RadonSeal I can use on the slab since I already have it, and get some Thoroseal for the walls. I am buying the biggest dehumidifier I can find, Frigidaire FAD954DWD 95-Pint Dehumidifier from Amazon. I'll run that for a good long time first and see if any readings change on my moisture meter. Is that even an accurate tool to be using? or am I wasting my time with it. It's just a simple Ryobi Pinless Moisture Meter set to the Masonry mode.

The RadonSeal supposedly is fine for a top coat of gypcrete as long as I follow the directions and brush off any glistening or pooling a couple hours after the last coat. It will allow for bonding of a topcoat.

As for taking care of things from the outside, the vinyl siding on the house only comes down to the bottom of the second floor. From there down the block is just painted with, from what I understand from what the previous homeowner told me, some elastomeric paint. The house looks really odd from the outside (see pic). I plan on bringing that siding all the way down. That should solve any dampness coming from rain hitting the block.

So here's what I think my plan of attack will be (I think):



 Run dehumidifier for the minimum of a week, maybe two like Canarywood1 suggested... but I'll get an eye on the moisture readings.
Grind the floors to open up the pours for bonding of both sealer and gypcrete
Apply the RadonSeal, let cure for 10 days or whatever the instructions said.
Clean the walls with some type of Efflorescence cleaner (RadonSeal makes one which seams easier than others. Spray on, let dry, brush anything remaining off. No caustic acids to worry about. Idk, though, sometimes easier isn't always better.)
Apply Thoroseal to the walls and let cure.
Apply a poly vapor barrier all around on the walls and run long to wrap under the framing bottom plates which will go in next.
Do some framing along the interior of outside walls so my bottom plates are on solid concrete and on top of the vapor barrier going down to the floor.
Then for the slab, either tile directly on the freshly leveled concrete, or more poly vapor barrier on top there too and a floating type engineered hardwood floor.
 I mean I think that's all I could try. I will probably get condensation behind that poly on the walls, but really what else can I do? This should solve any musty damp smell down there, and maybe the lowered siding might even prevent any of that extra moisture, right? New code around here in NJ (prob elsewhere too), requires new 1" rigid insulation on the outside of the house when new siding is put on. All together that should really solve everything, no? The house should be wrapped pretty tight from the outside, and sealed to the best of my ability from the inside as well.

Thanks so much for everyone taking the time to give your input. This is keeping me up at night and I am trying to get everything done quickly. The last thing I want is to procrastinate or run into some other problem and hit winter again. Once the cold sets it, there goes any hope of applying sealers or over pours or anything. I just want to get this done sooner than later.


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## stadry (Jun 20, 2009)

cold runs to hot & wet runs to dry just as mosquitoes run to people - don't expect a sahara climate,,, our dehumidifier in atl's set up for auto drain so we don't have to keep emptying the bucket :thumbsup:


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## Yodaman (Mar 9, 2015)

this may be of some benefit
http://www.buildingscience.com/documents/bareports/ba-0309-renovating-your-basment

the concrete should breath and dry to one side, if its sealed with mastic on the outside and covered in poly on the inside, moisture will be trapped.

Another aspect to look at is static pressure of the house. Stack affect of rising and escaping conditioned air can put the house into negative pressure. Which in turn will slowly pull moisture vapor thru concrete. Likewise a house under positive pressure will have the opposite affect.


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## sonnaps (Jul 21, 2015)

Yodaman said:


> this may be of some benefit
> http://www.buildingscience.com/documents/bareports/ba-0309-renovating-your-basment
> 
> the concrete should breath and dry to one side, if its sealed with mastic on the outside and covered in poly on the inside, moisture will be trapped.
> ...


This does make me rethink things completely. Maybe I should do nothing to the walls at all from the inside. Do what the PDF describes for a normal basement, even though mine in above ground. No cleaning per se, no grinding, no sealing.... just 1" of rigid foam insulation inside, my 2x4 walls to keep it in place, unfaced insulation, and sheetrock. Let the whole structure breathe and take care of any humidity or damp smell with the AC system or a separate dehumidifier.

My only question would be what the township and an inspector would say about this. Like would they consider it a basement, and not require any type of vapor barrier or faced insulation. Or would they require it like it would be on a normal first floor of a house?


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## stadry (Jun 20, 2009)

the only vapor barrier i have on the exposed bsmnt wall is the paper facing of the insulation - over that we placed 1" cedar for a finish'd surface,,, + we also run a 80pint dehumidifier

look at it this way - IF your town decided to offer free lunches to the homeless, would the number of homeless increase, stay the same, OR decrease ? in augusta, ga, they discovered free lunches attract, not repel or discourage :no: removing the humidity also creates space for addl humidity to penetrate/permeate :whistling2:


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## Yodaman (Mar 9, 2015)

Awful bad lunches and positive house pressure will might repel homeless and moisture vapors! Lol


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## Ron6519 (Mar 28, 2007)

Where do you live?


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## sonnaps (Jul 21, 2015)

Ron6519 said:


> Where do you live?


In NJ


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## stadry (Jun 20, 2009)

there shouldn't be much difference in moisture levels between belmar, avon, hackettstown, or allamuchy,,, now, IF you live in bergen or hudson county, you're f,,,,,,


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## sonnaps (Jul 21, 2015)

Monmouth County to be exact. There's a pretty small brook about 1000ft back behind the house.


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## concrete_joe (Oct 6, 2014)

if the grade has changed to keep water away you might get lower moisture, but it will always be an issue. its like painting using $50/gal paint over $2/gal primer. a dehumidifier running all the time will make the space unbearably hot.


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## stadry (Jun 20, 2009)

pls define 'unbearable' - ours runs in a 1/2 finished 44'x34' bsmnt w/closed mech room, exercise room, unfinished area, & 16 x 18 office,,, temp's always about 70f,,, i don't think that's unbearable for most folk

was in belmar last - storm took out the house 1/2 blk off the beach on 5th - good spot to live tho


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## sonnaps (Jul 21, 2015)

So I borrowed a smaller 50 pint dehumidifier from my buddy for now till the one I ordered gets delivered. In just a few hours the humidity dropped from 60% to 55% and I got about a gallon of water out of it. Don't know if that drop was all the dehumidifier or just that it got dark out. Right before I ran it it was 38% outside and 60% inside. After a few hours it was 48% outside and 55% inside so idk if it was because of pressure differences etc that helped... kind like the homeless person analogy lol.

So when will I notice a drop in moisture in the block and slab if at all? A couple of weeks of keeping the air in that downstairs area as dry as possible? or because of pressures will more moisture be just constantly pulled in from outside or wicked up from wet ground underneath? Am I just screwed?


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## stadry (Jun 20, 2009)

pressure's a minimal influence im-n-s-h-fo :laughing: you'll find a decent dehumidifier will overcome the vapor transmission rate & the place will be ('feel') drier - you'll be fine :thumbsup:


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## sonnaps (Jul 21, 2015)

You know how I posted I bought that RadonSeal already on impulse. I had done a quick test run on a few spots just to see if my moisture sensor will read differently on treated areas. I did this like the first day I posted here. I ground just one block, and two 1' x 1' square areas on the slab. Before application I was getting about 30% on that particular block and 60% on both spots in the slab. I did multiple coats of the RadonSeal on the one block as well as only one spot on the slab. It's been several days now and all three areas (even the ground down but untreated spot on the slab) read like 90%. That's gotta be because the area down there was sonhumid and the pours of the concrete were opened up right? Unless this RadonSeal stuff is still drying out. It's weird, the instructions say it would cure in 24hrs I think.


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## Ron6519 (Mar 28, 2007)

If the humidity is lower outside the house, you can just open the windows to reduce the humidity inside. The only time you need to run the machine is when the outside has high humidity.
As for getting hot in the basement due to the dehumidifier. That happens when you have the unit on too long. Set the unit to 55% and you won't have the issue.


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## sonnaps (Jul 21, 2015)

Ron6519 said:


> If the humidity is lower outside the house, you can just open the windows to reduce the humidity inside. The only time you need to run the machine is when the outside has high humidity.
> As for getting hot in the basement due to the dehumidifier. That happens when you have the unit on too long. Set the unit to 55% and you won't have the issue.


How about the time frame of the block and slab to dry out? Will those moisture readings drop? Is the dehumidifier going to do anything for that given a week or two?


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## Ron6519 (Mar 28, 2007)

sonnaps said:


> How about the time frame of the block and slab to dry out? Will those moisture readings drop? Is the dehumidifier going to do anything for that given a week or two?


The indoor humidity is the total result of the indoor conditions. If the humidity is lower outside. let the low humidity air into the basement.
If the block has moisture, it will move from the block to the air.
Same with the slab. Once it's in the air you can allow this air free to the exterior of the house by opening the windows.


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## Yodaman (Mar 9, 2015)

stadry said:


> pressure's a minimal influence im-n-s-h-fo :laughing: you'll find a decent dehumidifier will overcome the vapor transmission rate & the place will be ('feel') drier - you'll be fine :thumbsup:




The dehumidifier may keep up with vapor transmission and help with dampness. But regarding neg. pressure and affects on a basement humidity there is plenty to read on the topic. Although it is probably more relevant during winter months when the house is closed up. There may be some simple things that can be done to minimize it, like air sealing the attic. Clean the sofit vents. Are the soffit vents balanced with ridge vent as it pertains to net free area? Is there a attic exhaust fan with insufficient intake. Sufficient intake for all the other exhaust fans? A more drastic approach would involve whole house ventilation that could balance the pressure.

On another, but related note, if neg. pressure is enhancing vapor diffusion into the basement than it is also aiding with radon migration.


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## sonnaps (Jul 21, 2015)

Yodaman said:


> The dehumidifier may keep up with vapor transmission and help with dampness. But regarding neg. pressure and affects on a basement humidity there is plenty to read on the topic. Although it is probably more relevant during winter months when the house is closed up. There may be some simple things that can be done to minimize it, like air sealing the attic. Clean the sofit vents. Are the soffit vents balanced with ridge vent as it pertains to net free area? Is there a attic exhaust fan with insufficient intake. Sufficient intake for all the other exhaust fans? A more drastic approach would involve whole house ventilation that could balance the pressure.
> 
> On another, but related note, if neg. pressure is enhancing vapor diffusion into the basement than it is also aiding with radon migration.



I will definitely have to look into all of that and do some research on it. The sofit vents look fine, I had checked those a while back. There is no ridge vent, just one powered attic fan up there. It does kick in all the time. There are two gable vents on the sides of the house, but that is it.


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## sonnaps (Jul 21, 2015)

I think I am going to go on a slightly different route:



 Try to air the place out one way or another... open all the windows, run a dehumidifier, etc...
I'm still leaning towards grinding the floors to open up the pours for bonding of both sealer and gypcrete. Either way I need to level this floor.
Do some framing along the interior of outside walls so my bottom plates are on solid concrete. Instead of poly under the pressure treated bottom plates of the walls, I am going to go with these: BG63 Structural Gaskets http://conservationtechnology.com/building_gaskets.html 
No sealers of any kind anywhere, walls or slab... just do an overpour of the gypcrete minimum of 1.5" to level everything off.
Behind my framing I will sandwich 1" thick XPS foam insulation (still have to talk to the township and see if they require this mechanically fastened somehow to the block even though the 2x4 framing is holding it in place)
Do not forget about fireblocking... almost overlooked that but I have it covered now.
For the walls, just the 1" XPS foam insulation, then unfaced fiberglass batt in the stud bays, then mold resistant sheetrock (the green stuff). Everything can breathe, no vapor barriers that will trap the moisture and cause condensation behind the walls.
As for flooring, I am going to just stick with tile... maybe the wood look kind but just straight tile on the slab.
I know this floor is going to be cold in the winters. I just don't know what else to do besides busting the whole thing up and getting foam insulation under it and pouring a new slab that has some kind of thermal break from the outside footings. In a perfect world with all the money and time, I guess that's what I would do, but I can't right now. If I do radiant heat in my gypcrete overpour, I keep reading how I will just be warming the large concrete slab and anything attached to it, i.e. the foundation, etc. It would be a waste without that insulation beneath it and that thermal break.


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## concrete_joe (Oct 6, 2014)

you think fiberglass insulation doesnt hold water??

and if you are pouring 1.5" over the top then why not add some radiant floor heating now? the ground below is a heat sink to the joules you are adding, but its some loss of energy vs very cold floor, pros and cons for everything.

adding the foam underlay before the wood flooring will help keep the flooring warm (or not cold).


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## sonnaps (Jul 21, 2015)

concrete_joe said:


> you think fiberglass insulation doesnt hold water??
> 
> and if you are pouring 1.5" over the top then why not add some radiant floor heating now? the ground below is a heat sink to the joules you are adding, but its some loss of energy vs very cold floor, pros and cons for everything.
> 
> adding the foam underlay before the wood flooring will help keep the flooring warm (or not cold).


Actually I cam across Roxul insulation sold at Lowes. It seems like the perfect thing for a basement, even in my above ground basement.

You think radiant on that slab will be enough to heat the area? It's 1100 sq ft. You don't think I'll lose so much heat that I won't be able to keep the 1st floor warm?


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## concrete_joe (Oct 6, 2014)

sonnaps said:


> Actually I cam across Roxul insulation sold at Lowes. It seems like the perfect thing for a basement, even in my above ground basement.
> 
> You think radiant on that slab will be enough to heat the area? It's 1100 sq ft. You don't think I'll lose so much heat that I won't be able to keep the 1st floor warm?


dunno.


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## Yodaman (Mar 9, 2015)

sonnaps said:


> You think radiant on that slab will be enough to heat the area? It's 1100 sq ft. You don't think I'll lose so much heat that I won't be able to keep the 1st floor warm?


I think you could put enough heat into the surface of the slab to heat the space. The question is, how inefficient will it be? I have read some nightmare stories where uninsulated slabs were outfitted with radiant that were so bad the system had to abandoned. I would do some research on it.
Run a heat loss calc. or manual-J, should give you a good idea. If you have a boiler and can not insulate the slab for radiant, maybe consider baseboard heat.


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## sonnaps (Jul 21, 2015)

Yodaman said:


> I think you could put enough heat into the surface of the slab to heat the space. The question is, how inefficient will it be? I have read some nightmare stories where uninsulated slabs were outfitted with radiant that were so bad the system had to abandoned. I would do some research on it.
> Run a heat loss calc. or manual-J, should give you a good idea. If you have a boiler and can not insulate the slab for radiant, maybe consider baseboard heat.


The house originally had hot water baseboard, but I was going to switch to forced hot air strictly because of cost and ease of installation, especially since I have to do all new ductwork for the AC anyway. You think baseboard heat will keep the slab bearable as far as walking on it barefoot in the winter?


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## Yodaman (Mar 9, 2015)

sonnaps said:


> The house originally had hot water baseboard, but I was going to switch to forced hot air strictly because of cost and ease of installation, especially since I have to do all new ductwork for the AC anyway. You think baseboard heat will keep the slab bearable as far as walking on it barefoot in the winter?



I think the baseboard heat would be only marginally better than forced air regarding floor temp. The radiant heat from base board would only affect the floor temp at best a couple feet next to it. You would get your biggest bang for the buck regarding floor temp by insulating it with high density foam even if its without the radiant floor heat.

I have seen diagrams of radiant wall, but not sure of effectiveness.
Since this thread has morphed into heating, you may want to start another thread in the HVAC dept. 

Radiant floors are nice, but regarding ROI its hard to beat a HE hot air furnace.


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## sonnaps (Jul 21, 2015)

Yodaman said:


> I think the baseboard heat would be only marginally better than forced air regarding floor temp. The radiant heat from base board would only affect the floor temp at best a couple feet next to it. You would get your biggest bang for the buck regarding floor temp by insulating it with high density foam even if its without the radiant floor heat.
> 
> I have seen diagrams of radiant wall, but not sure of effectiveness.
> Since this thread has morphed into heating, you may want to start another thread in the HVAC dept.
> ...



Yes, I agree on starting a new thread in HVAC. Thanks for all the input everyone. I did manage to get a lot of information and suggestions to at least steer me in one direction.


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