If you are a DIY enthusiast and enjoy home improvement projects, chances are you have considered building the house yourself. One of the essential phases of the procedure is represented by the foundations; these are also necessary if you plan to build a garage, shed or swimming pool. There are a few simple steps to building a foundation that will stand the test of time; with a little hard work, patience and attention to detail, you'll have laid the foundations of the structure in no time.
Steps
Part 1 of 3: Laying the Foundation for the Foundation
Step 1. Determine the depth of the foundation
Generally, they must penetrate the ground for about one meter; however, there are several factors to consider. If you are digging in very wet soil, you need to go deeper; the same is true if you are building on a slope or close to it.
- There is a simple method for assessing the moisture level of the earth. Collect some soil with an empty coffee jar, leaving 7-8 cm of free space from the edge and fill the rest of the container with water; wait for the earth to absorb the liquid and repeat the procedure. Time the time it takes for the earth to absorb water; a rate of less than 2.5 cm per hour indicates a poorly hydrated soil.
- Sometimes, it is better to go to a professional instead of using home assessment methods. A construction contractor can run diagnostic tests and tell you everything you need to know about the land you want to build on; it can also measure how flat the surface is and determine whether or not you need to change the depth of the foundation.
Step 2. Make a project
This step is essential and must be carried out before the work begins. You must contact the municipal technical office to obtain the permits and licenses that allow you to lay the foundations and build the structure; You must also have the property inspected by an engineer who can provide you with important information about the land you want to build on.
Step 3. Clean the surrounding area
You need to clear the grass, roots, and debris around the foundation site. The moment of inspection is perfect for assessing the depth to which you need to dig. If the area is not level, use an excavator or shovel to level it.
Step 4. Use an excavator
You can also use a shovel, but it takes longer and you don't always get a precise job; the hole for the foundations must be greater than the foundation, at least 60 cm larger in each direction. This excess space allows you and the people who are helping you to enter the excavation and lay out the foundations of the foundations.
- The hole should be at least 60 cm wide and as deep, preferably 90 cm.
- Remember that you do not have to dig the entire area on which you plan to build the house, but only the perimeter of the building; the surface where the construction will be located is made in the next steps.
- After digging, use a shovel to remove any excess dirt and debris still in the hole.
Step 5. Arrange the rebar for the foundation bases
This is an indispensable job, because the concrete needs support beams, otherwise it will crumble. Purchase armor suitable for the type of bases you plan to build; you can then develop it upwards by connecting iron rods, available in most hardware stores.
- First lay the armor, then add the rods on top of it, spacing them about 60 cm from each other and keeping them 30 cm from the corners.
- Then, lift the armor and attach it to the rods; there should be a specific hook for this job. Do not use zip ties or twine as they will damage the bases.
- Make sure the armor is equidistant from all sides of the pit and from the bottom.
Step 6. Pour the first layer of concrete
This should be at least 60cm deep, if not more. You don't have to build large walls on top of a small first layer; standard guidelines indicate that it must be at least 40-50cm thick.
Make sure you are using the correct cement mix; if there is not enough water or there is too much cement, the compound does not dry properly. For more information, read this article
Step 7. Use a trowel to smooth the concrete
Make sure there are no cracks or crevices on the surface; this is an important detail, because the walls you will raise later must rest on a completely uniform plane. When the concrete is dry, you can use a level to check that it is level.
Part 2 of 3: Building the Foundation Walls
Step 1. Build the formwork
They are used to stabilize the foundation walls. The boards that form them must be about 60 cm wide and 3 m long, with a minimum thickness of 3-5 cm; the shorter side of the plank must face downwards, resting on the initial layer of concrete. You need enough planks to line the inside and outside of the base trench so that there are no gaps between them.
- You can pour some compost outside the outer boards to help them stay still and upright.
- Apply metal bars to the outside of the boards to keep them snug together.
Step 2. Mix the concrete and pour it to form the foundation walls
Again, remember to prepare the mixture with the right proportions; read this article for more details. Generally speaking, you should make one side wall at a time, also considering that its height above the ground depends on the level on which the building will rest; if you live in a low-lying area, the foundation walls need to stick out of the ground more.
Step 3. Attach one concrete wall to the next
After casting the first, you have to insert rods (small pieces of reinforcement) into the concrete, but not before waiting for the concrete to dry; subsequently, drill 3-4 holes along the sides of the wall, spacing them about 15 cm from each other; do this on both sides and insert the rods into the holes.
- This step is important because without rods the walls can move causing the building to collapse.
- Cast the concrete for the second and third walls starting with the first; the concrete hardens over the rods and joins the foundations together.
- Insert new rods into the sides of the second and third walls.
Step 4. Smooth the surface of the foundation
You can use a trowel to smooth out the top edge, checking that there are no cracks and crevices; you should use a trowel with a curved edge to smooth the edges.
Step 5. Remove the formwork
Wait for the concrete to dry and then remove the boards; you have to do this as soon as the concrete has stabilized, otherwise the wood will stick to it. Try to remove the planks from above to avoid damaging the foundations that have just been cast.
Step 6. Spray the walls with a waterproof coating
You can find this type of product in most hardware and construction stores at a low price; it is basically concrete in a spray can that allows the foundations to be coated with an extra protective layer, to avoid damage caused by water or other liquids. Remember to treat both sides of the walls.
Part 3 of 3: Laying the Foundation
Step 1. Throw some gravel, sand and / or ground stones into the space left between the foundation walls
Use a rake to distribute the material evenly, creating a layer no thicker than 2-3 cm.
Step 2. Spread a polyethylene sheet over the gravel surface
This material acts as an insulating barrier between the ground and the foundations, preventing humidity, which could rise, from causing cracks and fissures along the foundations; It is best to purchase a tarp tailored to the exact dimensions of the foundations you are building.
Step 3. Install wire mesh and armor over the insulation barrier
The technical specifications regarding thickness, width and other factors are indicated in the building regulations of the Municipality; the wire mesh is used to keep the concrete compact and avoid breakage.
You can also add spacers that lift it up and fit directly into the waterproof sheet; you need to put one every 5-8cm
Step 4. Add the radiant heating system and exhaust pipes
These pipes are placed along the outer edge of the foundations; if you don't install them, water builds up under the house damaging the foundation. Check if you also want to install an underfloor heating system; you have to mount it at this stage of the work, placing it just above the polyethylene sheet.
Step 5. Mix the concrete and lay the foundation
Check that the consistency of the mixture is correct; for more details read this article. You can use a trowel to smooth the surface and a trowel with a rounded edge to even out the edges; if you notice small irregularities in the concrete, wait for it to dry slightly. Next, sit on top of a piece of foam rubber (resting on the foundation) and use a trowel to finish the details.
Step 6. Insert anchor bolts before the concrete dries
You can buy them at the nearest hardware store; these are important elements because they ensure the construction at the base of the foundations. The anchors should protrude from the concrete for about half of their length, you should space them 30 cm from each other and place them 30 cm from the corners.
Step 7. Wait at least two months before constructing the building
You must allow the foundations time to settle in the ground; in this way, you can compensate for the natural slippage of the ground that can occur: you certainly do not want the house to collapse as soon as you start building it!
Advice
- Start with small projects, such as laying the foundation for a shed or gazebo. Having mastered the basic processes of this work, move on to larger and more complex constructions, such as creating the foundation for the house.
- Decide if you want to add elements such as the water drain or the radiant heating system before making the foundation; you have to take into account their position before pouring concrete.
Warnings
- If you are having difficulty with any of the steps described above, don't forget to ask for help from building contractors or engineers. Continuing construction despite doubts could lead you to inadvertently break civil construction laws or make critical mistakes.
- If you don't spread the sand or gravel evenly across the foundation base, you could cause irregularities or cracks in the concrete. make sure that the sand or gravel layer does not have large variations in thickness when you distribute it.
