Interior drains and barriers
Basement waterproofing in Hoover
Where a Hoover house stands on a slope, the basement is usually dug into the hill on one side, with a door or garage at ground level on the other. The wall that faces uphill holds back wet soil every time it rains. Interior waterproofing accepts that some water will reach that wall and gives it a controlled path to a pump before it can spread across the floor.
Call (205) 555-0115Drawing
Inside the wall: where the water is sent
- Outside digging. Shown for comparison. An interior system leaves the soil outside alone.
- Outside coating. Also for comparison: see the exterior page.
- Footing drain outside. Older houses may have one that has silted up. The inside drain does its job instead.
- Wall liner. A sheet fixed to the inside face catches seepage and steers it downward, out of sight.
- Drain under the slab edge. A strip of floor is cut out along the wall, a perforated pipe goes into gravel, and new concrete closes it.
- Sump basin. The pipe falls to a basin where a pump lifts the water and sends it outdoors.
How the inside system works
Water tends to show first at the joint where the wall sits on the footing and the floor slab meets them both. An interior drain is placed right there. A strip of slab, roughly a foot wide, is broken out along the wet walls. A trench is dug beside the footing, lined with gravel and fitted with perforated pipe. The pipe slopes to a sump basin, and the floor is patched with fresh concrete.
On block walls, small holes are often drilled near the base so water held inside the hollow blocks can empty into the drain. A wall liner or dimpled sheet may be added so damp on the wall face runs behind it into the same trench.
Nothing in this stops water arriving at the outside of the wall. It lowers the water level beside the footing and keeps the room dry. For most finished and unfinished basements that is the result the owner wants.
What paint and sealers can and cannot do
Masonry sealers and waterproof paint slow down damp passing through a sound wall. They are worth using on a wall that is only ever slightly damp. They do not hold back water under pressure. When the soil outside is saturated, the water finds the next gap, usually the floor joint, or lifts the paint off in blisters. If a painted wall is flaking and chalky at the bottom, that has already happened.
What the work does to the room
This is the disruptive part, and it helps to know it beforehand. Everything within a few feet of the walls being treated has to be moved. In a finished basement the lower part of the wall covering, the baseboard and the flooring edge come off along those walls, and carpet is rolled back or removed.
Breaking concrete is loud and dusty. Ask how dust will be contained, how the rubble leaves the house and whether the route crosses floors you care about. A furnace, water heater or oil tank standing against a wall may need to be worked around, which leaves a short untreated gap that should be marked on the plan.
Putting the room back, meaning new drywall, trim and flooring, is frequently a separate job from the waterproofing. Check which of them the proposal covers.
Ask before you agree
- Which walls get a drain, and why those and not the others?
- Where will the sump basin go, and where does its discharge pipe come out?
- Are weep holes being drilled in the block?
- Who moves the appliances and built-in shelving, and who puts the room back?
- What is the plan for a power cut during a storm?
- What does the written warranty cover, who stands behind it, and does it pass to a buyer if I sell?
What usually goes alongside
An inside drain works with less strain if less water reaches the wall. Downspouts carried well clear of the house and soil graded to fall away from it are the cheap half of the job, covered under yard drainage. A basement dehumidifier deals with the damp air that remains. Where one wall takes nearly all the water and can be reached from outside, exterior waterproofing on that wall alone is sometimes proposed instead of, or together with, the inside drain.
Basement waterproofing questions
Does the whole basement need a drain?
Not always. Water often enters along one or two walls, typically the uphill side. A partial system costs less but leaves the other walls as they are, so ask what happens if water later shows up there.
Will the new concrete match my floor?
No. The patched strip will look newer than the slab around it. Under carpet or laminate it does not matter. On a bare or painted floor it will show.
Can a finished basement be done without tearing out walls?
The bottom of the wall has to be opened along the treated sides so the drain can sit against the footing. How high the opening goes depends on how the wall was built. Ask to be shown on your own wall.
Is this the same as crack repair?
No. Sealing a single crack is a small job described under basement leak repair. A drain system is for water that comes in along a length of wall or at the floor joint.