Interior basement waterproofing
An interior system collects water at the base of the foundation wall and pumps it outside before it reaches the floor. It is installed from inside the basement, so the yard, the driveway, the deck and a septic bed are never dug up.
- Installed frominside the basement
- Seasonall year
- Works witha sump pump and backup
When an interior system is the right repair
- Water shows up along the line where the wall meets the floor after heavy rain, a thaw, or when the sump cannot keep up.
- The outside of the wall cannot be excavated: an attached garage, a deck, a porch, interlock, a propane tank, or a septic bed and its pipes within a few metres of the wall.
- The wall is concrete block. Water that enters anywhere up a block wall falls through the hollow cores to the bottom course, and an interior drain with weep holes is the way to let it out.
- Water rises through the slab as well as along the walls, which happens on the sand and gravel of the escarpment side of Caledon when the water table is high.
- The basement is going to be finished and needs a drainage layer behind the new walls.
How it is installed
- The floor is opened. A strip of concrete roughly 30 cm wide is cut and removed along the affected walls.
- A trench is dug beside the footing and lined with filter fabric so soil cannot wash into the drain.
- Perforated pipe is laid in clear stone. Clear stone is washed gravel with no fine particles, so water runs through it freely and the pipe does not silt up.
- A dimpled membrane goes on the wall. Seepage runs down behind it into the stone instead of onto the floor. On a block wall, weep holes are drilled into the bottom cores first.
- The pipe is run to a sump pit. The sump pump lifts the water and discharges it outside, well away from the foundation and never toward a septic bed or a well.
- New concrete is poured over the trench, level with the existing floor.
What it does not do
An interior system keeps the room dry, but the wall itself still gets wet from the outside. If the wall is block or stone and the mortar is already deteriorating, or the goal is to stop water reaching the wall at all, exterior waterproofing is the repair to look at. At the assessment we tell you which of the two fits your wall.
Finished basement? The bottom 60 to 100 cm of drywall along the treated walls has to come off to reach the floor edge. Tell us at the assessment and the quote will state exactly which sections are removed and reinstated.
Questions about interior waterproofing
Will there be dust in the house?
Cutting concrete makes dust. Wet cutting, plastic sheeting around the work area and a vacuum at the saw keep most of it out of the rest of the house, and the quote says how the area will be protected.
How long does installation take?
It depends on how many metres of wall are treated and whether the basement is finished. A single wall is a much shorter job than the full perimeter; the written quote gives the duration for your house.
Does an interior system need maintenance?
The drain has no moving parts. The sump pump does: test it twice a year by pouring water into the pit, and check that the discharge line outside is clear, especially before the spring thaw and after the leaves come down.
Can it be installed if the basement floor is below the top of the footing?
Yes. In older Caledon houses the slab often sits level with or just above the footing. The drain is placed beside the footing at the depth that exists, not dug below it, so the footing is never undermined.
Next step
See it for yourself at the assessment
We show you where the water enters and explain why an interior system does or does not suit that wall.
Book a free assessment