Site prep question

[1930]

Can someone tell me what the formula is for site preparation/ drainage away from house pad.

In other words how much of a slope should exist 50 or 100 feet away from home?

Nothing but loamy sand that drains well but im assuming at any distance from home there should be a drop in elevation and that the surrounding land should not be level with home pad.

I haven't gotten far enough yet to know but maybe there will be a requirement to build up or raise the home pad above grade level.

West central fl

 

[dodge man]

1% is not a bad number, that would be 1 foot of drop in 100 feet.

 

[newbury]

<snip>

Nothing but loamy sand that drains well but im assuming at any distance from home there should be a drop in elevation and that the surrounding land should not be level with home pad.
<snip>

How fast does it drain with the max rainfall event is the problem that needs to be solved.

Are you concerned about Florida, where you list your location?

Also what's the elevation? A lot of Florida is LOW and and relative to sea level is going lower.

Scientists monitoring Tampa Bay have updated the most conservative estimate for the expected rise in the bay during this century. That means they're no longer considering the National Oceanic and Atmospheric Administration's prediction of a 2-foot rise. The conservative estimate now is from three to 3 1/2 feet above current sea levels.

from New Estimates Show Levels of Tampa Bay Rising By At Least 3 Feet By 21 | WUSF News

So if you don't want surface water standing in the next 20 years I'd mound the pad up a bit.

For instance around my area in Mississippi lot's of places that normally drain after a moderate rainfall are in standing water, we've gotten over 20 inches of rain THIS YEAR, compared to a normal 10".

 

[1930]

High elevation for fl. No concern for flooding. No surface water in this area

 

[Complete Turf Care]

1% is not a bad number, that would be 1 foot of drop in 100 feet.

I agree with 1%. When I build football and baseball fields, I try to get 1%, however, I have been successful with 0.4%, but the water doesn't get off as quickly. I would not go more than 2%. That would get the water moving too fast.

 

[dodge man]

I will add the biggest mistake when setting a finished floor elevation is setting it to low. Less of a problem with basements more of a problem with slab on grade.

 

[1930]

Thanks guys, I had no idea, I thought I had to shoot for a much larger number

 

[nyone]

Yes to low can be real problems. To high can be adjusted by adding fill or stairs.