Learning how to install wooden posts is essential in the construction of structures such as geodesic domes, glamping cabins, and other rural buildings. In this article, we will guide you step-by-step on how to safely and securely install wooden posts for long-lasting results.
Site Preparation
Before installing the posts, it is crucial to have a properly leveled and demarcated site. During this stage, we prepare the ground, define the dimensions of the structure, and take key measurements to ensure a stable foundation. If you haven’t completed this phase yet, we recommend reading our article on Site Preparation for Building a Dome in Patagonia, where we explain the process step-by-step.
Defining the Location and Number of Posts According to the Construction Plan
To ensure a stable structure aligned with the design of the 6-meter diameter dome, it is essential to follow a precise scheme for post installation. In this case, a grid plan with 16 anchor points, spaced approximately 2.30 meters apart, was used to ensure an even load distribution.
Initial Reference Point
A starting point (marked in green in the image) is established from which the grid is drawn using reference lines with string or chalk.
- Measurement and Leveling: It is key to use a tape measure and a level to confirm that each post will be correctly aligned.
- Marking the Holes: Once the position of each post is defined, proceed to mark with stakes the points where the holes for installation will be dug.
Post Distribution by Size: Larger posts were selected for the central area, where the dome will be located, ensuring greater stability. In contrast, thinner posts were used for the corners and edges, sufficient to support the perimeter structure.
Post Treatment: Protection and Durability
Creating a Workbench for Post Treatment
To ensure proper treatment of the wooden posts, it is essential to have a stable surface where they can be safely handled. The use of a robust workbench specifically designed to hold the logs during the different preparation stages is recommended.
A key feature of this bench is the inclusion of a notch, which immobilizes the posts and prevents them from rotating. This detail facilitates the painting process, nail placement, and general wood handling.
Steps for Post Preparation
The post preparation process is crucial to enhance their resistance and durability over time. Below are the essential steps to ensure proper installation and protection.
1. Cleaning and Bark Removal
- It is recommended to use protective gloves and appropriate tools, such as a sharp machete.
- To facilitate the process, an efficient technique is to climb onto the post, position yourself as if on a slide, and begin removing the bark in a downward direction.
- The goal is to completely remove the outer layer until the clear and uniform wood is exposed, avoiding any residue that could promote moisture accumulation or fungal growth.
2. Protective Treatment: Application of Asphalt Paint
To ensure maximum post durability and protect them from moisture, rot, and other environmental factors, it is essential to apply asphalt paint. This coating creates a waterproof barrier that prevents water absorption, minimizes the risk of fungi, and significantly extends the wood’s lifespan when in contact with the ground.
For optimal protection, it is recommended to apply the paint to the first 50 centimeters of the base, which will be buried, ensuring that the wood does not absorb ground moisture. Additionally, it is advisable to extend the application at least 20 centimeters above ground level to reinforce protection in the exposed area, where the wood may be in contact with water, temperature changes, and other adverse environmental factors.
1. First Coat
- Mix of 50% asphalt paint and 50% mineral spirits.
- Uniform application on the lower part of the post to ensure product absorption.
- It is recommended to let it dry completely before applying the second coat.
2. Second Coat
- Mix of 80% asphalt paint and 20% mineral spirits.
- An additional layer is applied to reinforce protection against moisture and rot.
- Let it dry completely before proceeding with installation.
Additional Tips for Better Anchoring
- Tip 1: To prevent the post from accumulating dirt at its base during drying, it is recommended to place it in an inverted hole until it is completely dry.
- Tip 2: Use 4-inch nails at the base of the post to improve adhesion with concrete, increasing the structure’s stability and resistance. In this case, 3 to 4 kilograms of 4″ spiral nails were used.
Excavation and Post Fixing with Concrete
To ensure the stability and durability of the posts, an excavation with an approximate depth of 50 cm is recommended. This depth provides a solid foundation and minimizes the impact of ground movements.
Hole Preparation
To ensure a stable and resistant foundation, it is essential to properly prepare the hole where each post will be fixed. This process not only improves structural stability but also optimizes drainage and minimizes contact with moisture.
- Placement of stones at the base: At the bottom of each hole, place large stones between 15 and 25 cm in height. This stone bed creates a draining surface that allows water to pass, preventing moisture accumulation at the post’s base.
- Pouring concrete: Begin pouring the concrete in layers, alternating with the incorporation of stones strategically distributed within the mixture. This method improves structural resistance and increases volume, reducing the amount of concrete needed for each hole.
By employing this technique, material usage is optimized, concrete consumption is reduced, and soil drainage capacity is improved, ensuring a longer-lasting post fixation.
Mixing and Applying Concrete
For post fixing, a concrete mix with the following recommended ratio is used:
- 6 buckets of aggregate
- 2 buckets of sand
- 1 bucket of cement
- An antifreeze is added to the mix to improve resistance in cold climates. Based on the amount of material used, it is recommended to calculate the appropriate dose according to the product’s instructions.
It is recommended to mix in batches to avoid overloading the mixer, ensuring uniform application and preventing material waste. The mix should be neither too liquid nor too thick.
Fixing Process
Proper anchoring of the posts with concrete is essential to ensure the structure’s stability and durability. Below are the recommended steps for optimal fixing:
- Post placement: Position the post in the excavation on the drainage stone base, ensuring it is well-supported and centered.
- Teamwork and pre-fixing: It is recommended to perform this process with at least two people, so one can hold and level the post while the other pours the concrete. For greater stability, small supporting woods can be nailed between the post and the ground, preventing movement or tilting before the concrete sets.
- Pouring concrete: Begin filling the hole with the concrete mix, alternating with the incorporation of large stones to improve structural resistance and optimize material usage.
- Compaction: Using a metal rod, manually compact to eliminate air bubbles and ensure the concrete is evenly distributed around the post.
- Drainage slope formation: Once the hole is completely filled with concrete, leave an excess above ground level, shaping a slight “dome” slope around the post. This slope prevents rainwater accumulation and reduces the post’s exposure to moisture.
- Protection during curing: To prevent damage to the mix due to temperature changes or frost, place a nylon sheet over the post’s base, ensuring proper concrete hydration and avoiding premature cracks.
Working Without Electricity
This process was carried out in an environment without access to electricity, requiring alternative solutions to ensure work progress. For power supply, a gasoline generator (Blitz Generator) was used, which allowed the operation of essential electric tools. Additionally, an electric mixer connected to the generator was used, ensuring efficient concrete mixing.
Access to water was also a challenge. To solve this, a 200-liter tank was transported, and water was loaded directly from a nearby stream. The mixer was strategically positioned to facilitate pouring the mix into the wheelbarrow, optimizing the concreting process.
Materials
- Wooden posts: Can be purchased or prepared according to the process detailed in this article. The use of cypress, eucalyptus, or other resistant wood is recommended, avoiding pine due to its lower durability.
- Asphalt paint or waterproofing: Essential to protect the wood from moisture and extend its lifespan.
- Nails: Especially 4-inch spiral nails to improve fixing with concrete.
- Aggregate, cement, water, and stones: Essential materials for concrete preparation.
- Nylon: Used to cover the concrete during curing and prevent frost damage.
Tools
- Gasoline generator: Power supply for electric tools.
- Electric mixer for concrete: Allows for a homogeneous and efficient mix.
- 200-liter tank: Transport and storage of water.
- Wheelbarrow: Facilitates the transport of concrete and other materials.
- Square shovel: Ideal for mixing concrete.
- Pointed shovel (or heart shovel): Used for hole excavation.
- Sharp machete: Key tool for cleaning and debarking posts.
- Safety gloves: Protection against splinters and chemicals.
- Chainsaw: Facilitated post cutting and adjustment.
- Bucket: For handling water and concrete mix.
- Marking string and small nails: Used to define post alignment and leveling.
- Water level and tape measure: Essential tools to ensure proper post placement and alignment.
Frequently Asked Questions (FAQ)
How long does it take for the concrete to cure?
Curing time varies depending on temperature and the type of cement used. Under normal conditions, concrete begins to harden in 24 hours, but it is recommended to wait at least 7 days before subjecting it to heavy loads.
Is it necessary to apply asphalt paint to all posts?
Yes, especially in areas with high humidity or constant rainfall. This protects the wood from deterioration and extends its lifespan.
What alternatives are there to asphalt paint?
Acrylic waterproofing or high-resistance exterior varnishes can be used. However, asphalt paint offers one of the best cost-benefit ratios in terms of moisture protection.
Conclusion and Next Steps
Now that the posts are correctly installed, the next step is to build the base for the dome. Discover how to prepare a resistant and well-leveled deck in our next article.
