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below grade level slab - codes?

IWantToKnow

Member
Joined
Apr 23, 2013
Messages
9
Location
DC
Hi,

My condo building was a conversion of an old historic building. The builder used the original slab (although one section was opened up).

What's the code requirements for waterproofing/dampproofing so the basement units don't have their place damaged by moisture coming up? In addition, assume the moisture does come up through the slab and "wet" the engineering floor, how do we prevent it from occurring? The engineering floor is glue directly onto the concrete, and we don't know if the builder did any test on the concrete before installing.

Thanks,
 
ibc 2009 SECTION 1805

DAMPPROOFING AND WATERPROOFING

1805.1 General. Walls or portions thereof that retain earth and enclose interior spaces and floors below grade shall be waterproofed and dampproofed in accordance with this section, with the exception of those spaces containing groups other than residential and institutional where such omission is not detrimental to the building or occupancy.....

1805.2 Dampproofing. Where hydrostatic pressure will not occur as determined by Section 1803.5.4, floors and walls for

other than wood foundation systems shall be dampproofed in accordance with this section. Wood foundation systems shall be constructed in accordance with AF&PA PWF.

1805.2.1 Floors. Dampproofing materials for floors shall be installed between the floor and the base course required

by Section 1805.4.1, except where a separate floor is provided above a concrete slab.

Where installed beneath the slab, dampproofing shall consist of not less than 6-mil (0.006 inch; 0.152 mm) polyethylene

with joints lapped not less than 6 inches (152 mm), or other approved methods or materials. Where permitted to be installed on top of the slab, dampproofmg shall consist of mopped-on bitumen, not less than 4-mil (0.004 inch; 0.102

mm) polyethylene, or other approved methods or materials.

1805.3 Waterproofing. Where the ground-water investigation required by Section 1803.5.4 indicates that a hydrostatic pressure condition exists, and the design does not include a ground-water control system as described in Section 1805.1.3,

walls and floors shall be waterproofed in accordance with this

section.

1805.3.1 Floors. Floors required to be waterproofed shall be of concrete and designed and constructed to withstand

the hydrostatic pressures to which the floors will be subjected. Waterproofing shall be accomplished by placing a membrane of rubberized asphalt, butyl rubber, fully adhered/fully bonded HDPE or polyolefin composite membrane or not less than 6-mil [0.006 inch (0.152 mm)] polyvinyl chloride with joints lapped not less than 6 inches (152 mm) or other

approved materials under the slab. Joints in the membrane shall be lapped and sealed in accordance with the manufacturer's installation instructions.

Joints in the membrane shall be lapped and sealed in accordance with the manufacturer's installation instructions.
 
Hi, This is in DC and according to the website: The District of Columbia has adopted the 2006 I-Codes and NFPA’s 2005 NEC with changes, deletions, and/or additions set forth in the Construction Codes Supplement adopted December 26, 2008.

Do you know if the codes you mentioned above still applies?

Also, what are "other approved methods or materials?"

I guess my question is how do I know if the builder actually put in waterproofing or damn proofing materials.
 
IWantToKnow said:
I guess my question is how do I know if the builder actually put in waterproofing or damn proofing materials.
That would be difficult to accomplish without removing the slab.
 
I am assuming that the builder didn't remove the slab to put in the water proofing. For existing slabs, what's the requirement for builder to ensure moisture will not enter the living space above?

Thanks/
 
ICE said:
That would be difficult to accomplish without removing the slab.
Not if you use xypex, can be applied to either side of wall/slab

Xypex | Concrete Waterproofing using Crystalline Technology

Xypex prevents the penetration of water and other liquids from any direction by causing a catalytic reaction that produces a nnon-soluble crystalline formation within the pores and capillary tracts of concrete and cement-based materials.
 
Last edited by a moderator:
Xypex is a crystalline waterproofing that is added to the concrete mix. Therefore, it needs to be in the concrete when it is placed to create an effective barrier throughout the slab.

More likely, the problem is moisture vapor transmission (MVT). Since the building is of a historic nature, the basement was probably not intended for residential occupancy, and the introduction of air conditioning creates an imbalance of water vapor; thus, the moisture vapor drive is from the exterior (below the slab) to the interior (above the slab in the basement) to try and balance it.

There are surface-applied products that will reduce or stop MVT. Other alternatives are discussed in this article: http://www.icri.org/publications/2006/PDFs/janfeb06/CRBJanFeb06_Craig.pdf
 
Mark, you're correct. I checked their website and they do have coating products. I've only been familiar with their additive products.
 
a different way to ask

Hi all,

Thanks for all the replies. I would like to ask this question differently to see if I can understand better.

There is no doubt that the slabs need to have damp proofing or water proofing. Regardless of what the builder did or didn't do, if excessive moisture comes up (to the point of saturating the flooring_, isn't it evident enough that the proofing has failed and should be repaired? This is of course assuming no other sources that would add moisture to the flooring like pouring water down to the flooring.

I don't think the code would just say adding proofing but no other standards/codes to say what's satisfactory. I am interested to know at what point the proofing is considered a failure.

I do have a question. In the code mentioned by mark handler, it says damp proof is required except where a separate floor is provided above a concrete slab. What does that mean, like putting down carpet/woodfloor, or a whole story (so it's like a crawspace or unoccupied basement)?

Thanks.
 
IWantToKnow,

I guess my question is how do I know if the builder actually put in waterproofing or damn proofing materials.
IMO, ..a core drilling in one or two locations should provide the evidence that is desired.

The engineering floor is glue directly onto the concrete, and we don't know if the builder did any test on the concrete before installing.
The presence of water (presumably) coming up through the concrete floor might be

coming from a fluctuating water table, ..stopped up french drains at the "below grade"

locations, ..bad grading away from the foundation walls, ...downspouts directing the

water to the sides of the walls instead of away from the foundation, or a combination

of these components.

how do we prevent it from occurring?
This is where the fun begins! Someone will need to research carefully a lot of potential

contractors who can actually, correctly diagnose the problem(s) and provide a solution

for them, ..hopefully with some type of worthwhile warranty. Someone will need to

contact the various contractors who perform this type of service on a regular basis,

..has reputably been doing it for a number of years, ..offers an actual valid warranty /

guarantee, ..doesn't require payments upfront, ..has an actual contract versus a

"proposal", and maybe even offers references from previous clients, both satisfied and

non-satisfied.

This is a lot to ask of a contractor and the "someone" doing the search, but to get to

the actual causes of the problem(s), some good detective work will need to be

performed. Plus, this type project may take awhile to diagnose. Kinda like a doctor

trying to diagnose a problem with multiple symptoms.

This suggestion is a real "shot in the dark", but possibly contact the "Holmes On

Homes" t.v. show and see if they want to do a film shoot, or possibly "Ask This Old

House" for the same reason. These two shows seem to fix everything (on t.v. that is).

Does this help? :)

.
 
As long as I can say it's unaccpetable to have slab to emit that much moisture (to the point my engineered floor has 25-30% + of moisture content), I have a case to tell others to investigate.
 
As long as I can say it's unaccpetable to have slab to emit that much moisture (to the point my engineered floor has 25-30% + of moisture content), I have a case to tell others to investigate.
IMO, someone who is experienced and competent to provide an accurate analysis would

need to be hired.

FWIW, there are a lot of companies who make claims that they can accurately diagnose

these types of problems. Research, ...research, ...research, ...research, ..ask

lots and lots and lots of questions & references.

.
 
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