Hello all, first time poster!
I frequently read the breaktime column in FMB. I am a amateur carpenter getting ready to re-model an addition. The addition is un-insulated block construction with a poured concrete floor. The windows are single pane, steel frame type. Currently there is no return for the HVAC and ther is a terrible H2O problem. (wet walls, moist carpet, ect…) My plan is to add a return for the HVAC, stud out the inside walls to add electrical and insulation, drywall, and vinyl replacement windows.
My question is…
Should the replacement windows be installed in the block opening, or in the new framing when I stud up the secondary walls? Does it matter? Thanks for any and all insight.
Jeremy Holbrook
Replies
superhawk, I recently did the same installation you are describing. Removing the metal frame window proved to take more cuts than I thought. When that was out I needed a maintenance free stop in the block opening to set the window against.
The method I used worked very well. I basically cut a board that a piece of vinyl J mold would "snap" on to. In order to get the "snap" I had to have a board such that if you looked at it from the end it would look square with a corner notched out.
I attached the boards to the cement blocks, snapped on the J mold, and installed the window from the inside.
Hope this is understandable and helps.
Fonzie
Jeremy,
I would strongly recommend getting your HVAC work done first, so you can see if that cures your moisture woes. If it doesn't, the last thing you want is framing, insulation, electrical, drywall, new carpet, etc. soaking it up.
Could be a combination of events leading up to moisture--it would seem that adding returns may help, but where is the water coming from in the first place? Through the block walls, the floor, the windows? Is the subfloor tiled? Any sump pumps?
Thanks for your insight!
The block addition is built on a slab so there are are no sump pumps. Are there any precuations I should take before framing up the inside walls. ie. coat (paint) the inside of the walls and/ or floor with some product? Caulk the joint where the block wall meets the slab? I truely believe that the main proplem is the lack of return for the HVAC. The home has two 50gal. aquariums in it. I ame sure the HVAC system is pumping this moist air into the addition. The steel frame windows sweat something awful! The washer and dryer are also located in this room (more moist air). I want to do everything I can to keep moist air from the outside, out. (not much I can do about the aquariums) If the humidity is still high when i'm done, I guess a dehumitifier is my last resort.
Any thoughts would be GREATLY appriciated!
Jeremy
(superhawk)
> ie. coat (paint) the inside of the walls and/ or floor with some product?
You might have a look at http://www.xypex.com. Their "paint-on" stuff has worked on stucco for me. It goes on more like a concrete slurry than paint.
-- J.S.
If it were me, I would reinstall the vinyl window unit back in the block opening. Install drywall overtop the furred out jambs, header and stool, then install the trim casing in a "picture frame" fashion. However, you can opt for all wood casing/trim; complete with stool and apron trim if you desire.
Most likely when you tear out the existing metal framed windows, you will encounter a slight cavity around the opening where the window had been fitted into. As earlier mentioned, you will need to conceal this cavity...either by reinstalling the new unit in the same location, or dressing up the jamb opening with appropiate material. You can do either...it simply depends on the look you want...do you want your windows to look recessed when viewed from the exterior ( by installing the unit in the new framed area) or a recessed look when viewed from the interior( by reinstalling new window in original location)?
To me, reinstalling the new window at or near the original location would cause no visual difference when viewed from the outside, and yet, the 4 inches or so of additional jamb space gained when viewed from the inside wuld not cause the window to look unnatural. It would also be a lot easier to "bridge" the gap between the new framing and the block wall by installing jamb liner materials from the interior side, rather than have to hide this gap from the exterior side.
Just my opinion.
I normally reinstall the window approx. at the original location. I may alter it an inch or so forward or backward depending on the how the block walled jambs faired after removal of the old window.
Davo
Superhawk, I strongly agree with Mad Dog.....find out your moisture source beforehand, and solve that problem first. Unless you know how to correct this problem, your drywall will sooner or later get mildewed and moldy.
Davo
Thanks to everyone on there insightful replies!
I will take all your advice under consideration when working on this project. I am still left with one question though... I wondered if the window placement affected the insulation factor of the addition? Would the structure be better insulated if the windows were in the block or the internal frameing? Does it matter? I think I can make the windows look good either route.
Thanks again to all, this is truly a great forum that I will return to often!
Jeremy (superhawk)
superhawk, I think you want your window in the block opening. The more you recess it the more problem you will potentially have with leaks & flashing. And I may be wrong but I don't think it would look right recessed in farther??
Something I failed to mention about my experience was having to redo the angled mortar (falls away to the outside along the bottom of the window). That is a mechanical leak protection which would be complicated by recessing further.
I hope it was clear about how to mount a treated board on the cement block that you could snap (no nails necessary) a piece of wide vinyl J onto. The "snap" flipper on the J ends up against the block. The part of the J that has the nail holes is on the inside and the window rests against that side. This made a good caulking edge and easy-install maintenance free cover.
Fonzie
Just a few questions.....
Exactly where is the water coming from?
If the windows sweat....does the block sweat also?
How is the dryer vented?
Are the Aquariums covered?
Are there any house plants?
What is the humidity in the addition & the rest of the house?
Is this building on or below grade?
How much overhang on the roof?
Is the roof flat or pitched?
Is the roof possibly leaking?
Are there any gutters?
Is there a ceiling in this addition and is it insulated or open?
Where do the downspouts drain?
Is the exterior of the block wall painted?
How can the HVAC push moisture only into that room?
What is your climate/where do you live?
...........and one comment....ditto on fixing the water/humidity problem first!!!!
Your responses will allow for a little detective work on the water problem!!!!
.....................Iron Helix
Iron Helix, I think sweating is characteristic of metal frame windows. It is at least here in west central Illinois. It is just because the metal does such a through job of conducting the cold the frame frosts up under certain conditions and dumps it on the sill. I have seen the problem and various attempts to solve it around here- like marble window stool. Since there is such a difference between the R value of the wall and the metal window that is the point of condensation.
I will try to answer all your questions:
Yes, the block sweats (and molds!)
The dryer is vented through the block wall and vents to the outside.
Aquariums are not covered (and always need make-up water)
No house plants.
The main part of the house has vinyl replacement windows that sweat VERY little.
Building is above grade. (house on a 3' crawl- Addition 2' above grade on a slab.)
The roof has a 1' overhang and is pitched.
Ceiling is drywall with insulation in the attic. (R13?)
Downspouts drain about 3' away from the house. (plus the slab is about 2' above grade)
Exterior is Aluminum siding.
About the HVAC system. I guess that was an assumption on my part that it was adding to the problem. I KNOW the HVAC is sucking moist air into the return (Aquriums losing water)... Does the furnace dehumidify the air is blows out as heat? Or am I just recirculating the moist air in my house? BTW my furnace is not a high efficientcy unit.
Lastly..I live in SW Ohio (near dayton)
Let me know what ya think!
Superhawk
Let me preface what I'm looking for when I ask these questions....in the winter with gas forced air furnaces it is a natural sequence that the moist 72 degree air is vented up the furnace flue...and as it does so colder/less moisture laden air is sucked into the house...repeat the cycle everytime the furnace kicks on and you will lower the humidity in this type of house to less than 10% RH(relative humidity) .....which is dryer than most deserts.
But your house...inspite of the HVAC system the house air still has enough RH to condense on the interior of the block wall. The QUESTION is "Where is this water coming from that condenses on the block wall? Or is that wall just that cold.
I don't think the glass fish ponds are the problem...not enough surface area.
The dryer is vented....I am assuming it is not stopped up.
The furnace is vented...and I assume that the vent/stack is clean and functional. The combustion of gas produces large amounts of water vapor, carbon dioxide & maybe monoxide.
Same for the Gas Water Heater and bath exhaust fans.
All vents must exit to the exterior of the house.
Is the concrete slab transpiring moisture due to a lack of vapor barrier...try the rubber mat test. Put a flat backed rubber membrane on the concrete floor overnight...pick it up the next am....if you see a moisture shadow/footprint of the mat then the floor is moving moisture.
Buy a humistat at a local hardware store, take a reading. Take the temperature of the "weeping wall". and the rooms air temp ..consult a set of DEW POINT tables to determine the temp and humidity required to allow the wall to sweat. Or send me the wall's temp, the RH, and the room air temp and I will do the tables.
Be a water vapor detective..........................Iron Helix
By the way ....you don't happen to use a "ventless" fireplace in the house?
I-H,
No ventless fireplace. Dryer vent..OK Electric H2O heater.. Bathroom vent to exterior of house.
I forgot to mention that since the addition has sh!tty windows and no insulation, we keep it seperate (closed door) from the rest of the house. The addition is on the average 20 deg+ colder than the rest of the house. (in the winter)
Please help me understand how a furnace works. If the furnace draws return air into the HVAC unit, blows it across a heat exchanger (heated by propane flame) and then distributes the same air out the supplies. This seems to be a closed loop system...how can the moist air in the house EVER escape? The aquariums are always losing water, so how come it isn't raining inside our house (with all the humidity)?
BTW...I would almost guarentee that the slab has no vapor barrier.
Thanks!!
superhawk
The furnace is essentially several boxes within a box. The burners are at the bottom of an upside down set of boxes known as the combustion chamber which has a baffled vent to allow the hot combustion gases to rise up a chimney. The byproducts of propane with oxygen combustion are heat, lots of water vapor, carbon dioxide (incomplete combustion also produces carbon monoxide)all of which go up the chimney.
As they go up the chimney a vacuum is formed in the house which causes the dry cold air from the outside to find its way through windows, doors and any opening in the interior envelope of the house. This air is known as "make-up air".
The combustion chamber is surrounded by another box which has a blower attached and that circulates the air within the house interior past the sides of the hot combustion chamber to transfer the heat to the house. This is an almost closed loop, except for the combustion and chimney draft air which is stolen from the interior air to make heat.
The term Relative Humidity is commonly known and used in weather reports daily. Relative humidity is an expressed percentage of total potential saturation capacity of the air at a specific temperature. The greater the air temp the more water vapor that potentially can be held. The percentage of saturation is relative to the temperature and the actual amount of water vapor available.
The actual amount of water in grams in a cubic meter of air is called Abosolute Humidity. A cubic meter of air at 20 degrees holds considerably less water than a cubic meter of air at 70 degrees.
So as the furnace burns the "make-up air" that enters via the cracks is cold and has a low absolute humidity. When the "make-up air" enters and is warmed the amount of the relative humidity in the house is reduced due to the lack of water in the cold air. Hence the constant need to replace the water lost in evaporation from the fish tanks.
Winter interior relative humidity levels in cold climates should be no more than about 30% or glass window surfaces may sweat. If your windows sweat then the humidity may be to high. It is not uncommon to see relative humidity readings go below 10% where standard gas forced air furnaces are used for heating.
I still suggest that you purchase a Humistat ($10-15) so we can have some data to actually derive some values to apply to your water problem in the addition BEFORE you do your remodeling.
We need to know the temperature and relative humidity in the heated portion of your home and the unheated addition. We need to know the actual temperature of that block wall...an instant read thermometer will do the job. or an indoor outdoor thermometer with temp probe on a wire that can be taped to the cold block wall. I'll run the numbers for you.
Also do the rubber mat test on the concrete for moisture migration.
Sorry about the homework assignment!!!
.........................Iron Helix