concrete slab next to house foundation

[chester]

I am going to pour 2 ~8.5ft x 3.5ft slabs next to my house, right up to the foundation. I a then going to install a couple of 3x8 sheds on them (Arrow vinyl/steel). Anyway, my initial plan was this:

Pour the slabs at a slope, (1/4" per foot) leading away from the foundation, to ensure water is led away. I was going to accomplish this by having the boards on the sides of my pour sloped at the angle I want, and then using these boards to "level" the concrete out when it is poured, this giving the concrete its slope.

First, will this work? Will the concrete stay at this angle?

Second, is there another way to prevent water from flowing towards the foundation, besides this? I will have to shim the sheds up, and that will be a hassle, and I will have ~3/4" ridge at the entrance, which is somewhat undesirable. Could I pour the concrete true level, and then put something at the junction of the existing foudnation and the new slab instead?

thx

[tbasc]

As I understand it: The slabs will be covered by the sheds. The shed roof will determine where the water goes. The slab can be flat. The top of the slab should be above the ground level to exclude water. The slab should be separated from the existing construction so it doesn't bond with or hang up on the existing materials and can move independently. TB

[chester]

Thanks. That makes a lot of sense. I will plan on putting a spacer in the back. My only issue is, while the slabs will be almost enitrely covered by the shed roofs, the shed desgign is that the roof slopes back, so they will essentilly be directling water towards the house. On the other hand, the side of the house normally takes water from rain anyway, so I can't decide if this is a bad situation or not.

[chester]

Thanks. As I said, my main concern now is the shed design, which ia asingle roof, that slopes BACK. I am not sure this is a really bad idea or not.

[chester]

Well, it DOES sound like a bad idea, to be sure. I will not attatch the shed to the foundation. The idea would be, that the slab will be sloped away from the house mildly, and the water would run down the back and down the concreate away from the house. but it still makss me a bit uncomfortable. I dont have the sheds yet, so I cant really get a grasp of how it will be. I have given some thought to rigging a gutter system for the backs of the sheds, that would take the water away from the back of the sheds.

[John McGaw]

You say that the shed roof will be directing water toward the house. This, on the face of it, sounds like a bad idea. In fact, anything that directs water _toward_ the house sounds like a bad idea and most of us do a lot of work with gutters and drains and landscaping to make sure that water heads in the other direction. Where is it that the water will be going once it rolls down the shed roof and hits the house? Is there some escape route? Will it run down between the shed and the house and, if so, where will it go then?

I write this as one who spent many backbreaking hours demolishing two large concrete patios that were poured attached to the foundation of my older home and which, by design or shifting, were sloped to direct water toward the foundation. It made for a really ugly situation during heavy downpours.

[Edwin Pawlowski]

Yes, but put expansion joint material against the house.

The shed roof will direct some of it. If the roof is an "A" frame it will direct some near the house though. Other that holding an umbrella when it rains, a little pitch is the best way.

It's a shed, not a home for billiards tables. You won't notice the slight pitch.

[Don Young]

[chester]

Yeah after thinking about it, and thinking...well I could just put a roof over the sheds, and flash the roof... If I am going to do that, why dont I just bulid a shed on the foundation instead? So I cx'd the shed order, and I will just build my own shed to direct the water out, abut the shed roof with the wall of the house, and flash the roof. This will allow me to pour the concrete pretty much flat, and i will leave a

1~1.5" gap betreen the house foundation and the slab.

Thanks for the input

[Sherman]

My horror story has to do with termites coming into my home from between the slab and my foundation. I now refuse to butt up a slab to my foundation. I want a gap of 2 or 3 inches minimum so I can make a visible check of my foundaton completely around the house.

[Don Young]

[Slolrner]

replying to chester, Slolrner wrote: If it was me I would build a 3-inch curb from the foundation all the way across where it would divert the water from running onto the slab and you're going to pour concrete anyway you might as well make a little concrete gutter out of it

[trader_4]

Sounds like an ugly little ditch for dirt and debris to accumulate in that serves no purpose. I've seen lots of patios, never one poured like that. You just pitch it slightly away from the foundation.