Commercial & Residential Renovations:
Kitchen & Bath Upgrades :
Maintenance & Repairs:
Outdoor Living:
Restoration & Reinstatement:
Timber Retaining Wall Calculator
This calculator assists in estimating the materials required for building a timber retaining wall. By inputting the desired length, height, size of the retaining boards, and post spacing, you can quickly determine the number of posts, retaining boards, the total linear meters of boards,
Please Note: Walls with a height exceeding 1.5 meters require a building consent as per the New Zealand building code. Additionally, walls lower than 1.5 meters but subjected to extra loading, such as from a driveway, a building, or a steeply sloping bank, also necessitate a building consent. If unsure, it's advisable to consult your local council. It's essential to be aware that certain insurance policies may become void if retaining walls are not constructed and signed off correctly. In locations requiring a building consent, an engineer’s design certificate might also be necessary.
Retaining Wall Construction Guide:
Introduction:
A retaining wall can offer both functionality and aesthetic appeal for gardens or landscapes. It helps level sloping sections and shields earth banks.
Key Guidelines:
- Height and Consents: Walls over 1.5 meters, supporting driveways, or under load from steep slopes may require consultation with an engineer and building consent. Even without consent, walls must adhere to the New Zealand Building Code.
- Soil Types: Best suited for firm gravel, stiff clay, sand, or rock. Soft clay, peat, or made-up ground may need an engineer's consultation.
- Timber Retaining Wall: Use vertical posts (treated to H5 standard) supporting horizontal rails. Ensure drainage behind the wall. If timber treatment is copper-based, use stainless steel nails.
- Materials Needed: Treated timber posts and rails, galvanized nails, concrete, drain coil, drainage metal, geotextile fabric, and timber preservative.
- Setting Out: Maintain a minimum of 300mm gap behind the wall for drainage. Use pegs and string lines to set post positions.
- Post Installation: For walls over 1.5 meters or under significant load, the post depth should be specified by an engineer or architect. The guide suggests a depth of 1.3m with a slight slope towards the bank. Use concrete to secure the posts.
- Rail Installation: Nail rails ensuring they are level, starting from the bottom.
- Drainage: Essential to prevent water buildup. Lay metal, place drain coil, and use geotextile fabric to prevent silting. Fill with drainage metal and compacted material, ensuring a 300mm gap against the wall.
Disclaimer:
Please Note: While this brochure's advice and recommendations have been crafted with care, it's intended to assist those interested in estimating projects. Aries Builders does not accept responsibility for the advice and recommendations contained herein.
Timber Retaining Wall Calculator
Results:
Total Posts Needed: 0
Linear Meters of Boards: 0
Total Scoria Needed (m³): 0
Total Drainage Coil Needed (m): 0
Total Including Waste: 0
Materials Needed Treated timber posts and rails, galvanized nails, concrete, drain coil, drainage metal, geotextile fabric, and timber preservative.