Waterproofing Below Grade
How does water get into my basement?
Most poured concrete basements have cracks of some kind that occur during the curing process. This is very common at window openings, beam pockets, and sometimes at corners or elevation changes.
When the soil around the foundation gets wet, it creates a constant hydrostatic pressure against the wall that will push water into the basement, even through the tiniest crack. Moisture can also get into basements through capillary action which acts like a sponge and draws water from areas of high concentrations (exterior soils) to areas of low concentrations (interior basement walls) especially in the presence of minimal foundation protection.
DMX AG™ isolates these cracks and capillaries from the surrounding wet soil, to prevent this from happening, and provides a clear negative side drainage path for ground moisture to be redirected to the footing drains, eliminating lateral water flow into the basement.
DMX AG™ creates an air gap between wet soil and your basement wall, allowing the poured concrete and concrete block walls to breathe and provides a clear negative side drainage path to disperse any ground moisture that might find it way behind the membrane. Wet soil never touches the wall next to your living space, thus reducing the chances of water infiltration into the basement.
The DMX AG™ is made of HDPE which is an impermeable material to water, and when installed according to our installation guide keeps water exterior to the foundation walls. This means dryer basements for the end user, and a wider choice of finishing materials for completing a basement area.
Why does DMX AG™ have dimples?
The dimples in DMX AG™ create a negative side air gap that eliminates the hydrostatic load (pressure) that forces water into the foundation, via cracks and capillaries as discussed earlier. Without the dimples in DMX AG™ the product would be in direct contact with the foundation exterior, minus a negative side clear drainage path, that potentially could trap moisture against the wall should it get behind the membrane and force water intrusion into the basement. The key to the success of the DMX AG™ is the dimple for the control of hydrostatic pressure and ground moisture control.
Can water get behind DMX AG™?
In most cases – highly unlikely when installed properly. However, even if the sheet was damaged and water got behind it, the air gap would prevent water from getting into the home by diffusing hydrostatic pressure build up and providing a drainage path to the footing tile. Because there is no direct soil contact with the wall, water just drains down to the footing and away through the drainage system.
The configuration of the dimple structure allows for continuous flow of water along the path of dimples and air gap to the footing drain, and resists the transport of drainage water to the foundation wall. The “conical” shape of the dimple provides a low resistance to vertical water flow and minimizes lateral movement of water, providing maximum protection of the foundation wall from moisture contact with the wall.
Do I need special fasteners to install DMX AG™?
You will need DMX Quik Clips and plastic washers for attaching the membrane to the foundation. Use with 1¼ inch concrete nails for poured or concrete block foundations, and 1½ inch coated deck screws for ICF foundations.
DMX FlexTrim is available for sealing cut edges in the membrane where the flat panel has had to be trimmed off, such as around basement below grade windows or along the top of the membrane on a slope. For full details, download our DMX AG Installation Manual. What types of foundation can I use DMX AG™ on? Every type you can think of—poured concrete, Insulated Concrete Forms (ICF), block wall, and wood.
Can I use DMX AG™ for repairs and renovations?
Absolutely! DMX AG™ will protect everything from a modest crack in a residential foundation, to the stone foundations of century-old churches and homes.
We have heavy clay soil. Can we use DMX AG™?
Yes! We suggest installing an extra row of DMX Quik Clips in the body of the DMX AG to help stand up to the vertical pressure heavy clay soil can exert on the membrane and wall.
(See our Installation Manual for details.
Is DMX AG™ just for walls?
Not at all! You can use DMX AG™ for underslab vapour barriers, exterior wall protection, interior wall repairs*, built-up flower beds, retaining wall protection**, around culverts, and many other commercial or industrial applications. Keep watching as we come up with even more! If your application calls for more robust drainage than simply moisture protection, you can use our DMX Drain™ Geocomposite Drainage Boards which are economical and very effective.
* Check with local building Codes on the use of exposes plastics and accepted practices for interior uses
** Drainage is very important in retaining wall designs, ensure appropriate drainage is accounted for before installing DMX AG™ (ie; sand, gravel, DMX Geocomposite)
Can I use DMX AG™ without a perimeter drainage tile?
Yes, but only in areas where there has been extensive geotechnical studies done to determine that a drainage tile is not necessary and the local water tables are not expected to cause any problem in terms of load bearing for the soil conditions. Consult you local Building Code or Regulations on the implementation and requirements regarding the installation of weeping tile or drainage pipes as defined in the Codes or by a Professional Engineer competent in soils investigagtions.
BuildBlock Waterproofing Recomendations
There are many waterproofing systems from which to choose. Some are widely used with results you can count on and others are newer methods designed to save labor and material costs. Some of the newer spray-on membranes for ICF may have success based on the regional skills of the applicator so research your options and results before choosing one. Waterproofing options include:
- Self-adhesive 60 mil membranes with protection mat to protect membrane from backfill (ex. Tamko)
- Spray-on membranes (ICF-friendly)
- One-step mat type protection (ex. SuperSeal, DMX)
- Place a self-adhesive membrane (BuildBlock recommended):
- First the block was cleaned thoroughly of debris and the yellowing of UV breakdown (if any).
- An ICF primer was then applied to help the adhesive stick.
- The membrane was applied to the wall starting at 1’ above backfill grade and rolled downward, overlapping 4” and terminated 4” or 6” over the footing. (Use an adhesive caulk like MP1 to help the membrane stick to the concrete or seal this bottom edge.)
- An ICF-friendly mastic was used (Hydrocide 800 B) to cover all terminations in the membrane, top and sides, on the outside of all seams.
- A protection mat by Carlisle was attached at the top of the wall and draped over the membrane to stop backfill damage ( backfill material punching or tearing holes in your membrane).
- The Platon waterproofing system:
- One step application barrier product with hangers and termination strips. (NOTE: more hangers are recommended.)
- 6” overlap
- System creates air gap between wall and backfill to stop hydrostatic pressure.
- Peel & stick membrane around the top is not yet installed.
Note: BuildBlock assumes no liability on basement waterproofing. Seek your local supplier for application methods. A leaky basement means problems for years to come.
The picture below speaks loudly about waterproofing, basement walls, brick ledges, and how to prepare for natural grade footings that will tie into your basement walls.
WHAT TO SEE
This basement wall has been built to receive a stick frame structure on top. Note the anchor bolts.
This project had three places in which the house’s footings and stems
were intersecting with the basement.
The contractor included three piers in the basement footings.
The elevation of the piers were built to be the height of the bottom of the footings for the house on grade above. (Note: The basement was smaller in size than the structure above.)
The rebar in the pier was later bent into the footing trenches dug into the backfill and then encapsulated by the new footing concrete on-grade.
The reason for this method is that an absolute bearing pier allows for no movement in backfilled soils and the basement wall will suffer no penetrations regarding tie-in steel or other attempts to tie a basement wall into a footing for a structure above. Without this method, many foundation leaks have been created.
The walls and the steel-mold formed brick ledge were waterproofed by the 60 mil self-adhesive membrane.
In this case, the installer placed penetrations through the mat to hold it in place under the brick ledge. This could cause water leakage into the basement cavity.
A Carlisle protection mat with silt cloth was applied as described on the previous page except for on the brick ledge detail.
Easy access of 4” from the wall to the pier so the wall could be properly waterproofed.