If you build a concrete foundation, or part of your house is mostly concrete, you need to consider waterproofing concrete to keep your house nice and comfortable. Concrete houses actually do not require as much waterproofing as houses with other types of structures, what needs to be considered in a concrete house is only cracks, joints or window and door openings. See Step 1 for more information on how to waterproof, and which waterproofing technique to choose.
Step
Part 1 of 3: Preparing the Concrete
Step 1. Determine if your concrete house needs waterproofing
Core concrete, precast concrete panels, and Insulated Concrete Form walls (ICF), are inherently more waterproof than other construction methods, meaning that additional waterproofing is rarely required. However, the exterior walls of precast concrete are usually coated more for appearance rather than for weather proofing or resistance to weather.
If you think your structure needs waterproofing, find a contractor you trust for consultation. He or she may suggest using a liquid membrane and not much else, or suggest filling in cracks or joints instead of doing more detailed and thorough waterproofing
Step 2. Prepare the selected walls for waterproofing
If you decide to do waterproofing, most of the techniques used will require the concrete walls to be in good condition. It means:
- Putty - for filling joints or cracks larger up to 0.6 cm, with a good quality polyurethane putty.
- Concrete filling - for filling joints larger than 0.6 cm, make sure the concrete filling is dry before proceeding.
- Sharpener - to smooth rough and uneven concrete so that the waterproofing membrane can adhere to a flat surface.
Step 3. Clean the concrete surface thoroughly before waterproofing
With a stiff brush, TSP (trisodium phosphate) and water, wash off any loose material, oil, or dust that is still adhering to the concrete. Most membranes require a clean surface to adhere to. Let dry before continuing.
Part 2 of 3: Choosing a Waterproofing Technique
Step 1. Use liquid membranes for speed and cost savings
Liquid membranes are usually polymer-based coatings that can be sprayed, sprayed with a trowel, or roller directly onto the concrete. The advantages of this waterproofing method are that it is quickly applied and the cost is relatively low. Follow the manufacturer's instructions for applying it.
The downside of liquid membranes is that their coverage is uneven. Even if you are coating at a thickness of 60 mm, the minimum recommended thickness, it is difficult to produce a consistent coating
Step 2. Use self-adhesive membrane sheets for a more consistent coating
These self-adhesive membrane sheets are large rubber bitumen membranes that you peel and place directly on the concrete. Sheet membranes are heralded for an even thickness, but are more expensive (for both, materials and labor) than liquid membranes, and take longer.
- Sheets of self-adhesive membrane are extremely sticky. You'll have to peel the membrane very carefully to reveal the sticky side, as it will stick to anything it hits, and once it's in place it's impossible to get it back off.
- Be sure to pay attention to the way the membrane sheets stack up against each other, as improper installation can cause leaks. Make sure the joints are cut properly and bead mastic for each joint, spaced thirty centimeters from one corner.
- The membrane sheet requires at least two people to install it. Installing it yourself is sure to produce poor results and frustrate yourself.
Step 3. Try an exterior insulated finishing system or EIFS
EIFS offers a durable, attractive and fairly simple coating on the outside of concrete walls, double-duty for insulation and waterproofing. For finishes such as stucco, the EIFS finishing coat can be applied directly to the concrete, filling existing holes, smoothing out minor defects, and producing a good moisture-resistant surface.
The EIFS is trowel-applied, and is available in 18.9L buckets pre-mixed and colored according to your choice. Apply with a Styrofoam block or rubber for an even surface and texture. Other EIFS products can also be sprayed, brushed, or painted with a paint roller
Step 4. Try cemented waterproofing
Cement waterproofing, besides having a moniker, that takes a mouthful, is easy to mix and easy to apply. Buy it at a building supply store. Mix with acrylic to blend well, and then apply with a long stick brush. The drawback of cement waterproofing is that it is less elastic, so it tends to crack after a long time of application.
Step 5. Try sodium bentonite if you want to use a "green" waterproofing method without the police
. Sodium bentonite is used in many city dumps to prevent liquid seeping into the ground. Basically sodium bentonite is clay or clay, which will serve as a good waterproofing if you are worried about leaving human footprints. Bentonite also has the advantage of being able to coat smooth and rough surfaces.
Part 3 of 3: Finishing and Other Considerations
Step 1. Know which walls can be waterproofed
Deciding which walls need waterproofing can save time, money and avoid headaches. This is the rule for determining which walls need waterproofing: any walls with soil on one side and living spaces (including narrow spaces) on the other. Here are tips to consider:
- If the area is wet (think Seattle, or the jungle), you may really need waterproofing for all the walls.
- Extend the waterproofing at least 0.3 m from the wall or any surface that requires waterproofing to the wall or surface that does not require waterproofing. You need a little buffer, or just to be sure.
Step 2. Apply your chosen finishing system to the walls according to the manufacturer's instructions
Depending on the waterproofing method you use, the manufacturer has instructions and best practices for applying it. Refer to the instructions on the product, or consult a contractor for the best results.
Step 3. Apply a roofing coating that fits your roof when using concrete roofing molds
This is an unusual situation, but there are houses with concrete roof molding and usually roofing cement and fiber roll for roofing is applied to the roof to prevent water from seeping in.
If the house doesn't have sufficient slope to allow water to escape from the roof when it rains, you may need to apply a tar or synthetic waterproofing membrane directly to the concrete, or use a seamless rubber roofing system. This product is more suitable for use by professional contractors
Step 4. Remember to make good drainage in addition to waterproofing
Waterproofing will not be of much use if running water does not find a drainage channel to escape. Consult an expert to build rain shelters, under-drainage piping systems or even sump pumps to move large amounts of water. If you need to dry your basement, read on.
Tips
- Check the VOC (volatile organic compound) label on the material you selected for this project. Several regulations limited the release of VOCs and strictly enforced their prohibition.
- Underground construction is more problematic in waterproofing. Many basements are built in areas where snow accumulation causes severe water seepage, causing the basement to become wet and requiring the installation of a sump pump and dehumidifier to drain it.
Warning
- Read and follow the manufacturer's instructions carefully. These products may contain hazardous chemicals, vapors, and other product hazards when applied.
- Use the necessary safety equipment, such as safety glasses and a respirator.
