Have you ever gone down in your basement and noticed a smell, one that really isn't pleasant. The smell may be mold, or mildew, or even urine from the family cat. And speaking of the cat, the smell may even be a dead mouse. Another smell can be concerning and that is sewer gas. When you have a older home, you may have a smell from a previous water leak. If you have a sump pump in your basement, this may not even be strong enough to help with those ugly smells. Blockages in your plumbing, and drains, venting and heating systems, are also causes of certain smells.
That mold and mildew in the basement is a growth of bacteria arising from stagnant moisture. It can be slow growing, or even rapid growing at times. Mold smells are usually tangy, earthy like, similar to decomposition. This mold is always present unless your home is in a arid area. One rule of thumb is, the more moisture you have in your basement, the more mold you are going to have. Remember, your home's basement is under the ground. So those cracks you see in the wall, or cracks in windows all contribute to mold.
Some people notice after a good rain their allergies are worse. So keeping your basement free of mold and mildew will help with this problem. A dehumidifier helps a great deal, also sealing any leaks or cracks is a great help. If your home does not have gutters, try investing in them, they keep any rain away from your home. But doing all the right things does not mean you are always going to keep mold and mildew at bay. Your basement just might always have a small amount of musty smell to it.
Another fix is to throw any carpet, furniture or other fabric away. This will also get rid of the mold and mildew, as well as the smell. These things are absorbents. Then cleaning thoroughly with a bleach solution will be a big help. You can place smaller items outside in the sun, to lose the smell as well as the mold.
There are case's that the mold and mildew problem is so severe that you need professional help. Getting your furnace and vents cleaned get rid of dust, debris, and any dead bugs. And even mold. Clean vents should be done every one to two years.
Now those smells of poop, rotten eggs, or even garbage means you have a bigger problem other than mold. This could mean you have a sewer gas smell, and this can be toxic, and in the wrong amount even explosive. This smell may be noticed only when the home is closed up and you have the heat or ac on. This smell is due to a build up of waste, which could be in your public sewer system or septic system. Smelling this gas could mean you have a clog or crack in the plumbing system. You could also have a clog or crack in your homes venting pipes. Venting pipes can be a part of your homes plumbing which poke out through your roof. These are not exhaust pipes, these are for fresh air. If alot of air is entering the drain pipe it will push air in front of it towards your sewer or septic system. These vents replace lost air. Also you may be smelling sewer gas due to plumbing fixtures traps that are now dry. If you plan of being away from your home for any length of time, you may want to get someone to flush your toilets for you. Toilet water can evaporate quicker than you think. These sewer problems can be serious and should be handled by a professional.
If you have a cat and there is urine, it can be pungent and pervasive. Cat owners know this smell. Plenty of products are on the market that can help rid this smell. But the best way is to treat it the same as mold, and go through the same process. Except with cat urine you should also get rid of any wood or wallboard that has cat urine on it. If it has cat urine on it get rid of it. Spread baking soda liberally, vacuum and this will help lift the smell. Kilz for the stained walls will come in handy, it is also good for wood.
The last smell is the ugly smell, sickly, sweet, and of decomposition. Yes, the smell of a dead mouse. And that smell is usually coming from inside the wall. And the only way it is going to be gone, is with time.