The crawlspace is the area beneath your home which allows electricians and plumbers access to wires and cables. Crawlspace covers are used to provide ventilation and to seal this portion of your home.
The area under your home should be kept free from moisture. Using crawlspace vents makes that possible. There are a number of different sizes of crawl space covers which you will need to consider for different reasons and purposes.
Most building codes still require the use of crawlspace vent covers as an adequate way to ventilate an area; however, the most recent codes don't actually require them. Some building scientists have discovered that vents can actually make the moisture problem much worse in certain climates.
Choosing the Size
There are quite a few different sizes and types of crawlspace covers which can be used to seal the entry to your crawlspace. They are essential, as they provide your house with a certain degree of protection from floods and other problems. When choosing the size of the crawlspace covers, there are quite a few different things that you will need to consider.
Whatever type of crawlspace cover you decide to install, you must ensure that it's fully waterproof. The main purpose of these covers is to protect your property from flood water and various other problems associated with lying water. Ensuring that the vents are waterproof ensures that you home will be safe from floods.
If you live in an area with a very hot summers and cold winter, then you will need to find a way to close the vents during the winter months. There are a few ways to do accomplish this end, but some of the easiest are to use crawlspace doors rather than covers. These are doors which can be closed and shut. Some of them are also water tight to provide extra flood protection.
If you are installing access covers into a crawlspace then the covers need to be large enough for you to comfortably gain access. Ensure that there is enough space to do whatever you need to do through the opening.
Crawlspace covers must be made from a material which is light enough to be lifted easily to allow easy access.
The US is a large country with a varied climate, which means that the type of vent that works in one part of the country will not necessarily work in another. It is very easy for the vents to crack and become damaged during changes of temperature.
Don't insist on buying the cheapest cover possible, as they aren't always the best option. Consider using something much more durable and long lasting. A slightly more expensive metal cover should last longer and be more stable.