The Stovebolt Site Forums The Shop Area Paint and Body Shop Garage Ventilation Question NOW WITH PHOTOS

Friends, I have a truck storage question... I just bought a house and it has a detached garage made of cinderblock built to waist height, then brick up another 8 feet or so. The roof is all wood with asphalt shingles. Garage built probably around 1920-40. I live about 0.5 miles from the Ohio River, so it gets humid.

There is definitely too much moisture in the garage which needs to be remedied as I dont want my truck rusting away. There is currently no airflow. Do you all have any advice on the best way to vent the garage? Im looking for specific types of vents, preferrably vents that dont use any/too much energy.

Please keep in mind that i live in an urban area, so i cant just crack the windows/doors of the garage for security reasons.

Thank you!

Does your garage have a dirt floor or concrete?

I installed a thermostat controlled Home Depot 120v attic gable-fan in one of the gables in my concrete slab, wooden 2-car detached garage with workshop. Make sure there is another open gable to supply air. Pulls the Central Florida heat out pretty good, especially in the open attic. I guess it pulls the humidity down to the outside ambient level. It comes on at a preset temp. So it doesn't operate at night or on cool days.

What, typically, is the relative humidity inside the garage compared to outside?
Also, as asked previously, what is the floor composition?
Can you send a picture of the garage?
I don't know if I can help but, I do mould remediation which is due almost entirely to inadequate ventilation.

Thanks guys, the floor is poured concrete with no visible cracks on the surface.

The relative humidity on the inside of the garage is more than the outside for sure. There are NO ventilation areas. We took out some old wood doors and most of the doors had mold/warping on the bottom of the doors. So i think the water either came in from the walls or who knows.

Ill work on pictures today and repost ASAP.

Thanks!

For a garage gable end vents are most likely adequate. No power required and they are inexpensive. If the gables are lined up with the predominant air flow pattern (N to S) the air flow will be better. Put a couple of 8x16s on each end to start with. You can always upsize or add more later if necessary.

The roof doesnt have gabled ends... ill have to get those picures up ASAP. Thanks, Kevin

If you don't already know how this'll help you.

OK folks, here are the photos of the garage inside and out... please let me know what you think about the venting. Thanks

Garage Photos

Uh, what venting?

Looking at the pictures I see that it looks like about 1/3 of the garage is below grade on 3 sides. Also, it appears to be a new poured concrete floor.
Firstly, concrete block and poured concrete are very porous and are not in the least moisture resistant.

The idea solution would be to dig down on the outside of the foundation and waterproof but, I think is rather draconian for what you require.
Because the floor is slab-on-grade I would not worry too much about it. Any water will run away from the front of the garage unless the floor slopes to the back which it does not appear to do.

If it were my garage I would first seal the concrete block walls with some sort of masonry paint (dont' worry about the brick which is above grade).
Install some sort of roof vent or even just crack open one of the windows. Just get the air flowing somehow and I think you will be fine.
Keep checking the humidity levels inside the garage and see how you are doing.
There are other more drastic steps to take but, start with the basics.
Peter

Looking at the pictures I see that it looks like about 1/3 of the garage is below grade on 3 sides. Also, it appears to be a new poured concrete floor.
Firstly, concrete block and poured concrete are very porous and are not in the least moisture resistant.

The idea solution would be to dig down on the outside of the foundation and waterproof but, I think is rather draconian for what you require.
Because the floor is slab-on-grade I would not worry too much about it. Any water will run away from the front of the garage unless the floor slopes to the back which it does not appear to do.

If it were my garage I would first seal the concrete block walls with some sort of masonry paint (dont' worry about the brick which is above grade).
Install some sort of roof vent or even just crack open one of the windows. Just get the air flowing somehow and I think you will be fine.
Keep checking the humidity levels inside the garage and see how you are doing.
There are other more drastic steps to take but, start with the basics.
Peter

Peter, what type(s) of roof vents specifically? Im trying to get specifics if possible.

Also I cant crack my garage windows, as I said we're in an urban area and I wont leave the old 51 out at night in the garage with any possibility for harm.

Thanks for the review...

Thanks, Kevin

I agree with Peter H, seal the lower concrete walls and floor. I think you have enough cracks in the physical structure to be able to install a solar attic fan to remove the moisture in your garage. But it would be best if you can add soffit venting or a vent in the door.

Installing an expanded metal gaurd on your window might add some extra protection from vandals, but not fool proof. You can also block off the window and add a solatube for lighting. These work great.

I noticed from the staining on the floor and wall that you will get water inside the garage. Sealing alone may not prevent this. You may have to dig a trench under the rear window and the left side and install a french type drain. You will have to drill a hole in the retaining wall to allow the water to exit. Not easy, but it will help keep the moisture to a minimum. As it stands now, you get all of the drainage from your garden behind the window, trapped at the wall with no place to go but the garage. This would be a great time to waterproof the exterior walls too.

The patch on the walkway looks useless to me. I would remove it and reseal the area against the wall. Even applying some bitchathane and a flashing would be better than what you have now. It would look better too and remove the tripping hazard you have now.

These are all things that you can do yourself or with limited help to keep the expenses down. Installing solar fan. The attic fan and solatube are probably the only high cost items, unless you hire out the french drain. Install the fan now and do the rest when you get the money and time. An alternative to the solar fan is the turbine fan. The attic fan information guide may help you decide what you need to do, although you are doing ventilation for the entire garage, I think the material covered will help with this installation too.

From you pictures it looks like the old knob and tube wiring system has been removed and you have no electricity to the garage. Thats' why I recommended the solar fan and solatube lighting.

Just a thought.
Step 1.Remove the rear window. Take about 20% of the top portion of the opening, build a box to accept a ventilation fan. (perhaps a small explosion proof barn fan with built in loovers.)Install a new window in the lower portion of the opening.
Step 2. Remove a few panes of glass from the doors & install new windows with a glass screen combination. Wire up your fan to a humidestat set up and you should be good to go. I actually did this for a friend and its been working well for over 9 years. Works good for taking out fumes etc.

Just my 2 cents
Hope this helps

Let me start off by saying that I am an old-house-hugger. Congrats on buying an old house and garage. You have a good looking and structurally sound garage of the era. I would try to avoid making changes that are not reversible. Your local historic preservation officer may have some suggestions.

I agree that water is seeping though the rear concrete block wall. Sealing the outside of the blocks below grade plus adding a French drain are good suggestions. Looks like your gutters are in good shape and carrying roof water away from the foundation.

You could probably lower the top sash of the rear window and install a fan like vickraft suggested without removing that nice looking original double hung window. Soffit vents would allow air to enter without defacing the garage doors.

I would be wary of puncturing the roof. Any time you cut a hole in the roof for fans, skylights, etc., you are creating an opportunity for leaks, plus it detracts from the original look of the garage.

OLD HOUSE STUFF:
If you are near Louisville, stop by Architectural Salvage, WD Inc (614 E. Broadway). It's a great architectural salvage company for parts for your new (old) house and garage. Also, subscribe to "The Old House Journal". The website is pretty good, too. This is not the same mag as "Old House Magazine".

You could install a whirlybird on the rear hip. It wouldn't be seen from the front and would draw the air out. Sealing the walls and floor will help also. Whirlybirds can be picked up at your local box stores.
Dan

You just need two kids to open and shut the garage door 50 times a day, that will air it out!

A shingled ridge vent could help, but you'll need to add soffit vents for air flow. That system is inexpensive to install and is easy enough to DIY if you have any carpentry skills.

Thank you guys, youre helping me keep the 51 rust free... Adios!

Add soffits, roof vents. With the windows, at least go to menards and buy a can of window paint. It will at least let the light in and not allow seeing in. For the sidewalk between the garage and fence, I would rip it out and re-pour it. I would place a PVC drain running to the alley. Make sure you have rain gutters and downspouts running to the alley too. For the cement walls, I would pressure wash and dry completely and then use bridge sealer on the inside walls and floor.
http://www.unitex-chemicals.com/products/epoxyproducts/bridgeseal/default.aspx
I use this stuff on my shop floor and garage floor. I just add some floor grit to it and it works great. It absorbs into the cement.

ON teh left side I noticed a pours and shaped concrete "cap" as if some one wanted to keep water from gettin gunder the wall. Also I seem to notice that if you are looking toward the read there seems to be a "drain stain" onthe white it kind of light in color so I was wonder if when it rains hard you get seepage.

I have the same problem on a work shop I closed the wall in. I'll live with it for now, but will need to take down the outer sheathing and address it probaly next year, water seepage is messing it up.

This might seem like a crazy idea. Research other garages of that era and see if any had some sort of a small a cupola installed. And maybe some louvers in the lower portion of the door. That may help preserve the character.
If you're not worried about looks, just add some roof vents. That should fix the ventilation problem, but you will still need to address the moisture issues like the others have already suggested.

BTW: That's a cool looking garage.

John

Least expensive -" Whirlygig" exhaust fan on roof near peak ( wind powered ). Add a couple of vents to lower part of garage door or mandoor.
Better solution - install an electric vent fan near peak of roof, controlled by humidistat. Install a couple of vents low down around perimeter.