By admin 
A blind area (also known as a perimeter paving or foundation apron) is an essential element of any building’s foundation, protecting it from atmospheric precipitation and groundwater. It is a horizontal or slightly sloped strip made of concrete, asphalt, tiles, or other materials surrounding the building perimeter. The main function of the blind area is to divert water away from the foundation, preventing moisture penetration, damage, and cracking.
This article provides a detailed step-by-step guide on how to make a blind area, from site preparation to finishing. It also covers material selection, installation techniques, and maintenance tips. The guide is suitable for both professionals and DIY enthusiasts.
What is a Blind Area and Why is it Needed
A blind area is a structure around a building that acts as a barrier against rain and meltwater. Without it, water flowing from the roof can accumulate near the foundation, causing damage and increased basement humidity.
Besides foundation protection, the blind area prevents soil erosion near the building, which can lead to landslides and deformations. It also improves the building’s appearance by providing a neat and finished look.
Depending on climate and soil type, the blind area may serve additional purposes, such as forming the base for walkways or platforms around the house.
Choosing Materials for the Blind Area
Material choice depends on budget, climate, and aesthetic preferences. Concrete is the most common and durable option. It is strong, waterproof, and resistant to mechanical stress.
Asphalt is a more economical alternative but less durable and requires regular maintenance. Tiles or paving slabs allow decorative finishes but require quality base preparation and waterproofing.
In some cases, gravel or crushed stone with geotextile is used, which facilitates drainage but is less reliable and suited for temporary or auxiliary solutions.
Preparing the Site for the Blind Area
Before starting work, the site must be carefully prepared. The topsoil is removed around the building to the width and depth of the future blind area, usually at least 20-30 cm. This creates a level and stable base.
Next, the site is leveled, and roots, stones, and debris are removed. It’s crucial to ensure a slight slope away from the building, typically 3-5 degrees, to prevent water pooling near the foundation.
After leveling, the soil is compacted to prevent subsidence and increase strength. Sometimes a layer of sand or gravel is added to improve drainage and leveling.
Installing Formwork for the Blind Area
Formwork shapes the concrete pour and defines the blind area’s dimensions. It is made from wooden boards, plywood, or special plastic forms.
When installing formwork, ensure the top edge is level and accounts for the slope away from the building. The height corresponds to the blind area’s thickness, usually 10-15 cm.
Formwork must be securely fixed to withstand concrete pressure and prevent deformation. It is removed 1-2 days after concrete pouring, once the concrete has set.
Creating a Sand and Gravel Base
Before pouring concrete, a base layer is prepared to distribute loads evenly and prevent cracks. The first layer is sand, 10-15 cm thick, moistened and compacted.
A layer of gravel or crushed stone, 5-10 cm thick, is placed above the sand. This layer improves drainage and prevents water accumulation under the blind area.
The base must be even and tightly compacted. Geotextile may be placed between layers to prevent mixing and enhance strength.
Waterproofing the Blind Area
Waterproofing protects the foundation from moisture penetration through the blind area. Bitumen mastics, roll materials, or polyethylene film are commonly used.
Waterproofing is laid over the sand and gravel base, tightly abutting the foundation. This prevents water from seeping under the foundation and increases durability.
Ensuring waterproofing layer integrity and proper connection to the walls is critical. Insulation layers may be added if necessary.
Pouring Concrete Mixture
Concrete pouring is the key stage in blind area construction. Use concrete grade M200 or higher with plasticizers for strength and waterproofing.
Concrete is poured evenly and compacted with a vibrator or poking rod to eliminate voids and honeycombs. Special attention is given to areas near the foundation and edges.
The surface is leveled with a screed or trowel, maintaining the required slope. To prevent cracking, concrete is covered with plastic and kept moist during curing.
Installing Expansion Joints and Reinforcement
To prevent cracking, reinforcement and expansion joints are used. Reinforcement is done with metal mesh or rebar 4-6 mm in diameter.
Expansion joints are technological gaps that compensate for thermal and shrinkage movements. They are placed every 3-5 meters and filled with elastic sealant.
Proper reinforcement and joint installation significantly extend blind area lifespan and prevent damage from loads and temperature changes.
Finishing and Final Works
After concrete curing, finishing can begin. Decorative tiles, stone, paint, or special coatings improve appearance and protect the surface.
For tiled blind areas, joints must be properly filled with sand or special compounds to prevent weed growth.
Finishing includes surface cleaning, smoothing irregularities, and slope verification. Installing curbs or edging protects the blind area from mechanical damage.
Maintenance and Damage Prevention
Proper maintenance prolongs blind area life. Regular cleaning from debris, leaves, and snow prevents moisture buildup.
In winter, use anti-icing agents that do not damage concrete or corrode reinforcement.
Cracks or chips should be promptly repaired with repair compounds and sealants. Regular inspections help detect problems early and avoid major repairs.
Comparative Table of Blind Area Materials
| Material | Strength | Waterproofing | Cost | Installation Complexity | Durability | Aesthetics |
|---|---|---|---|---|---|---|
| Concrete | High | High | Medium | Medium | High | Low (without finish) |
| Asphalt | Medium | Medium | Low | Low | Medium | Low |
| Paving Slabs | Medium | Medium | High | High | High | High |
| Gravel/Crushed Stone | Low | High | Low | Low | Low | Low |
Conclusion
A blind area is essential for foundation protection and building longevity. Proper installation requires careful site preparation, material selection, and adherence to construction technology.
Step-by-step execution from site prep to finishing and maintenance ensures reliable moisture and mechanical protection. Regular care and timely repairs keep the blind area in excellent condition for years.