Drainage Information
True or False? "Foundation Shrubs" are called foundation shrubs because they're planted near the foundation. This is true. However, the purpose of foundation shrubs is to protect your foundation from soil erosion. During hard rains such as thunderstorms and gulley washers the gutters over flow spilling onto the ground below causing soil erosion. Evidence of this can be seen as dirt splashing up on the foundation and soil pitting where the water spills over. It can also be seen on mortared patios, walkways, etc...The mortar eventually breaks down and erodes leaving spaces between the stones or bricks. When water sits in these spaces and freezes it will then pop the surrounding stones or bricks.  Solution: Plant shrubs 24-30", depending on the eventual size of the shrub, from the foundation. The foliage and/or branches will disperse the rain water and inhibit soil erosion. Once established, the shrubs roots will also provide soil stabilization. 

**NOTE :  Soil erosion can also be exacerbated by undersized or improper gutters. (SEE BELOW)

Gutters
Gutter size is determined by many factors.
1)  Roof Pitch - A roof pitch of 4/12 - 5/12 is considered a lower pitched roof. A roof pitch of 6/12 or greater is considered a more steeply pitched roof. Increasing the roof pitch increases the square footage of roof, amount of surface area water, and also increases the speed of the rain water.  Definition - 4/12 = an angle of 12' horizontally,(x axis) and 4' vertically,(y axis). 
2)  Square Fottage of Roof - The more square footage, the more surface water coming off of the roof.
3)  Roof Style A "Hip" roof style roof generally has a higher pitch. Also, "multipitched" roofs generally have connected gutter systems. Example:  A little dormer is connected to a lager dormer which is connected to a main roof and is then exited by only one down spout.
4)  Shingle Composition  - Increasing the dimension of shingles can slow down the rain water velocity. Flatter shingles and metal roofs can cause a water sheering effect.

Increased square footage and higher pitches = larger gutters and down spouts.

Having said all of this if you the signs of erosion on the ground? LOOK UP! There can be several problems with gutters:  Undersized gutters, undersized down spouts, clogged down spouts and/or gutters, incorrectly pitched gutters, a gutter that has pulled away from the roof or been bent out by a fallen tree limb. All of these can be potential drainage problems causing soil erosion below. However, gutter problems can be easily remedied and not costly, but left unattended can cause costly repairs. Ask your landscaping maintenance person check and clean your gutters regularly.

Improper Grading on New Homes
This is my personal pet peve. Many times I'm called to new homes about water problems and I find that the grading around new homes is insufficient. Many builders it seems, are not heavily concerned about grading because recent building codes require drain tile and sump pump installations. The grading still needs to be corrected by adding soil around the foundation to pitch away from the foundation. Otherwise, the sump pump can run continually, costing you more in electricity because the sump pump is recirculating the very same water. This is an ugly thought. Also, check the sump pump exit site for soil erosion. At the very least there should be a splash block underneath that is pithed away from the house.

Long Term Erosion & Pests
Long term erosion can lead to a wet sill plate and/or water leaking into your basement. The sill plate of your house is the horizontal 2 x 4 or 2 x 6 board that sits on your foundation. In newer construction, by code this board has to be pressure treated with chemicals to inhibit water damage, but that only slows down the process. Also, if the sill plate stays wet the vertical framing will wick the moisture up and those boards are not pressure treated lumber.

Water infiltration causes obvious damage, but also causes damage not as obvious to many homeowners. Wet wood attracks Carpenter Ants which suck the moisture out of the wood and leave what's called "frass". This is the leftover chewed wood. Rotten and decayed wood attracts Termites. Termites actually eat rotten wood. That's their job. They are considered a beneficial in the woods, not a pest, and eat fallen, dead, rotten trees, breaking them down into good humus for living trees. They are good at their job and therefore can do serious damage to your home if left unattended. All the pesticides in the world will not get rid of them. Like so many others in nature - removing their food source is the only real solution. Pesticides are only a bandaid and very costly.

If you have rotten framing it needs to be replaced. The affected part needs to be cut out and new boards "scabbed" in by a professional.