is this from the general allowance of moisture in the basement or can this be from some leaks that are not easily seen by the ***** eye and are unseen cracks in block foundation? if so, do i use the water hose method to find the leaks and seal them? what if i do the water hose thing and still dont see anything resembling a leak?

a guy whom i think makes a lot of sense wrote this in another thread...

"If you have mold, you have moisture, because mold cannot exist without it.

Possible causes of moisture are:
1. Damaged, insufficient, or missing vapor retarder under the floor slab. Cure: remove the floor (not as bad as it sounds), place a properly installed vapor retarder, and pour a new floor slab.
2. Cracked or otherwise leaking foundation wall or walls. Cure: hose test to find the areas that are leaking, then excavate to the footing, apply thick coat of dampproofing, and embed a waterproof membrane in the dampproofing, then backfill with pea gravel.
3. High water table, meaning higher that the basement floor all year round. Cure: install foundation drains piped to daylight, or to a drywell located far from the house, and while you've got the excavation open, waterproof the walls as above.
4. If you have a storm trap, it may be clogged, causing water to back up. Cure: have a good plumber snake the storm trap.

If you have only moisture but not water, the problem is probably either a faulty vapor retarder under the floor, or insufficient dampproofing on the foundation walls.

If you have water in the basement, then the foundation walls are suspect, either insufficient dampproofing, cracks, holes. etc. Cracks outside the wall can admit water and still not be visible inside the walls. Also possible are unsealed openings above ground in the foundation walls, such as uncaulked basement windows."

the front porch is a concrete slab that is seperated from the foundation and has heaved and is now sloped towards the foundation! is this a good place to start???

this will be my first project regardless... to remove and replace the porch and pour a new slab. should it somehow be attatched to the house or be seperate? as far as moisture in the basement, i am thinking i will dig down to the footing in this area and waterproof it. what do you think?

First, understand that there is no "general allowance for moisture in a basement". A well-constructed basement will not be moist.

How old is the house? Why I ask is that before a certain date, maybe in the 1950's sometime, no one used vapor retarders under the floor slab, and to compound the damage, floor slabs were often thinner than the now-standard 4 inches. Another reason why I ask is that after a certain date, maybe sometime in the 1970's I'd guess, builders often stopped using thick brushed-on coats of dampproofing (black stuff) and started spraying it on, often in thicknesses not much greater than paint.

Another cause COULD be cracks in the foundation, or openings above ground that allow water into the block cores, which will then find its way down to the bottom and create dampness if not visible water.

The hose test is a good place to start. It may or may not pinpoint leaks. If not, then I would dig down a little bit and expose the foundation that is now below grade...about two feet should be enough, in one small area. Look at the thickness of the dampproofing (black stuff), and look at the thickness and condition of the parging (cement plaster) on the foundation.

The dampproofing should show a measurable thickness (at least an eighth of an inch) and the parging should be thick also, over a half-inch, and should show no cracks or missing sections. If either or both do not meet these standards, then you might have found one cause, at least, of your moisture problem.

As far as the floor is concerned, if the house is older than 50 to 55 years, and maybe even a little younger, it probably has no vapor retarder under the concrete. If you have headroom, you could place a vapor retarder on the existing floor and pour a new 4-inch floor on top of it. If not, then if no other cause has appeared, you might consider removing the floor slab, installing a 4-inch gravel bed (might require a little digging), placing a vapor retarder, and replacing the floor slab with a 4-inch slab.

The front porch slab is a problem. If you simply replace it, what will keep it from heaving again? Perhaps, if you placed it on a deep (about 8 inches) bed of coarse gravel, you MIGHT avoid heaving. Otherwise, the porch should have a foundation that extends below frost level and bears on undisturbed soil. However, you want to try to avoid a porch foundation that ends in the middle of your main foundation wall, because the footings CAN place a lateral load on the foundation and possibly cause bowing of the main foundation. If it were my house, I think I'd stick with the slab on a healthy bed of coarse gravel...like maybe 1 1/2-inch crushed stone. And do NOT tie it into the house at all.

Do some investigation and tell us the age of the house, and we'll talk again.

This message has been edited. Last edited by: Richard Hetzel,

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Often musty odors in the basement are just the result of high humidity. Moist air is heavier than dry air and will settle to the lowest point in the home. When the moist air contacts a cool surface, ie underground foundation walls it condensates, creating dampness which leads to mold. A good dehumidifier may completely eliminate your problem. Don't be mislead by the latest scam the inside diverting companies are pushing, a ventilation system which is nothing more than an extremely expensive exhaust fan. This system is marketed under many names, but it is iether a humidex, or some sort of variation. Many professionals from the hvac industry have expressed concerns with this system causing dangerous conditions in a home because it is not an air exchanger as claimed, and can create negative pressure.

richard, thanks for chiming in. i must confess i have not even moved into the house yet but it was built in mid 70's... i move in the first week of march.

and this may shock you but the exposed foundation has no parging on it!! when we looked at the house with the agent we noticed the appearance of this right away and he was the one who explained what parging was and that it would make the house look so much better (i knew what it was, just didnt know what it was called and that it had other uses other than cosmetic) i can see up to 3 courses of block in some places. i actually looked into getting this done for asthetics before realizing that it might be a cause with moisture in basement. that being said, how far down do i go with the parging? i mean how far below grade? i now believe this PART of my problem.

once i move in i will dig down about 2 feet to determine the damproofing.

the porch slab... i meant by "replacing it" that i will dig down considerably and backfill the right way and power tamp to avoid the heaving issue. and yes, tying it in with the house is a moronic idea, cant believe i asked that....guess i was just thinking i wanted a clean seal between the slab and the house so that water could not go in between but i dont think it matters if you backfill/tamp properly.

Most homes are not parged above grade. Drive around and look. Just my opinion, but I would repair any cracks with hydraulic cement, and use a good waterproofing paint to seal above grade foundation.

I don't know where other people live, but where I do most of my work, every basement wall is parged from top of footing to top of wall, and THEN dampproofing is applied over the parge in the area that will be below grade. There is almosr no such thing as a concrete block that will not absorb water and allow it into the hollow cores, and once it's in there, it can be everywhere.

An unfinished concrete block foundation is seen only on very substandard houses.

88bimmer, what you need to know is whether the wall is dampproofed below grade. Dampproofing is that black stuff that is applied to the foundation wall. If it is dampproofed, the next thing you need to know is, was it applied by spray or by brush, and how thick it is. The thinner it is, the more likely it will, or already has, failed.

Sooooo...let us know what you find, and we'll take it from there.