Sparging the Blocks

[gto65goat]

Contractor should complete the Block build today.
Contractor says he will Sparge the blocks to 8 inches below grade.
I'm wondering, what if anything to do with the rest of the blocks (below grade)?
I never discussed it with my contractor, but I know there is a black in color product that usually gets spread on blocks below the surface (I believe this is done to keep water from invading inside the perimeter of the blocks?)
Can someone enlighten me?
Thank you,
John

 

[PAToyota]

The term is "parging" - basically a coat of mortar over the block. The black coating you refer to is an asphalt coating for waterproofing. Basically, unless you have a basement under your garage it will do nothing for you.

 

[gto65goat]

PAToyota,
I appreciate the reply.
Parging not Sparging.

I'm not sure I agree with you on NOT water-proofing of the blocks.
If I don't water-proof them...doesn't this allow moisture to invade to the "inside" perimeter of the blocks...thus causing more moisture to be combatted by the moisture barrier laid prior to the cement floor?

Thanks to all for replys and suggestions.
John

 

[OldCarGuy]

I would recommend “parging” and coating with black waterproofing all the foundation blocks that are below grade level. And have drain tile at the footer level topped with at least two feet of river stone. To combat moisture problems in the garage floor. However I live in an area with a high water table.

 

[Ironcrow]

Yes, seal below the grade. I prefer bags of Thoroseal mixed with water and Acryl 60.

 

[PAToyota]

We never specify waterproofing on foundation walls unless there is an interior space behind it. The water will also come up through the soil below the slab, so you'd actually have to waterproof both sides of the wall in your case.

Footer drains for a slab on grade is generally unnecessary as well, unless you have extenuating circumstances like OldCarGuy's high water table...

Now, if your floor is below grade - say the garage is set into a hill a bit - then that changes the situation and I would waterproof the exterior where the grade will be below floor level and include footer drains.

 

[brownbagg]

pa is right, there is no different from water outside the footing and water inside the footing coming from below. but if you want to waste money go ahead,

 

[mshedb]

Now, if your floor is below grade - say the garage is set into a hill a bit - then that changes the situation and I would waterproof the exterior where the grade will be below floor level and include footer drains.

How do the footer drains work? Do you drill a hole through the footing (or block) and run the pipe out above or at grade?

 

[PAToyota]

A footing drain runs around the outside perimeter of the foundation wall, sitting on the top of the footing. It has to slope downwards and exit to daylight.

Although you will almost always see the drain drawn beside the footing, the contractor will almost always put it on top of the footing because they just trench the hole for the footing and pour it without forms. Placing the drain beside the footing would either entail forming the foundations or digging down beside the footing after pouring the concrete - neither of which the contractor is likely going to want to take the time to do. This is why I usually detail the footing an extra block course below a basement floor with the first course being four inches wider than the rest of the wall for the slab to sit on. Then the drain will definitely be below floor level.

 

[KELLHAMMER]

In basements, I usually recommend to trench the footings below the rough basement excavation. Once footings are placed and walls are up. Add 4" crushed stone at floor, then the slab. That allows the drainage pipe to rest on the footing and be below the top of slab. Drainage Pipe is always placed outside the foundation and covered with stone wrapped in filter fabric. This pipe should be run to out-of -grade if possible. For basements Tuff n Dri is the best waterproofing . Code doesn't require waterproofing for crawlspaces or frost walls. But, I always recommend water proofing for any foundation that has living/garage space on the inside. Much easier to do it then, than to have to come back later to try to remedy a foundation leak. I'm mixed on having large areas of slabs with the edge resting on footing. Slabs can settle. I guess it depends where your building. In my area an experienced mason told me never to do it. Especially in garages. his argument was the slab will most likely crack there, since most likely the rest of the slab will settle under the weight of the cars. Maybe it's OK if the excavated area is stable and won't compress. Usually there is some disturbed fill that doesn't get properly compacted. So settlement is and issue in my area. One of the largest houses I ever designed was almost entirely on a slab(radiant heat system). The edges had to rest on the foundation. We had large areas of 5 to 6 feet of fill above grade. We used crushed stone since it has a tendency to be self compacting.

 

[elsensei]

The stuff to use is called Vulkem. Google it. I'm using it on my garage b/c i had a drainage issue and didn't want to take any chances, so in addition to running one subsurface and two surface drain lines, i also coated my stem walls with this stuff. It's basically liquid rubber that dries into a flexible membrane. Great stuff.