House design plan and making the foundations

by admin on October 17, 2012

The most basic part of the house design plan is the foundation drawing and the footing detail.

Although the drawings are fairly simple the volume of work required to construct them can sometimes be under estimated.

wall outline drawing

A lot of work has to be put into constructing the foundations to ensure they can withstand the loads exerted on them by the rest of the building structure.

There are many different types of foundations, choosing the right one depends on several factors. The safest option is to contact an architect surveyor or building control officer for advice. They will perform several tests and calculate the type of foundation required.

Constructing the foundations is one of the most exciting part’s of the build. For a start it’s the first of the trades, and the commencement means that a long cherished dream for building a house is now coming true.

Step 1 – Equipment Checklist

The tools required for laying concrete foundations include

  • String for setting out
  • A brush for possible surface finishing and cleaning up
  • A float for finishing surfaces
  • Hammer nails and steel pins
  • Straight edge for leveling pegs and formwork
  • Timber for pegs, formwork and tamping beam
  • Tape measure
  • Rake for moving concrete
  • Wood saw
  • Spirit level
  • Shovels

Step 2 – Setting out the site profile

site profile

The first task is to set out the site using steel pins, string lines and some aerosol spray.

Using the foundation plan begin to take scale measurements from it.

A good place to start is the entrance, insert a steel pin at the corner point which should be marked on the foundation drawing as the center line.

Check the corners are at right angles.

Repeat this for all the corners of the building including internal load bearing walls.

Then tie a string line around each.

Once the guide lines are complete mark out the profile like shown to the right.

Remove the steel pins and string lines and store away, they will come in useful later in the project.

Ordering concrete and digging the footings

First of all calculate the volume of concrete required for all the house foundations order approximately 5% more than the estimate.

Begin by digging a trench 2ft (600mm) wide dug to a depth of 4 ft (1.2m) meters deep.

This could be done by hand a small workforce or you could hire in a JCB and operator which could get the footings dug ready for concrete in less than a day.

Order concrete online

Step 3 – Pouring and laying the concrete

Concrete will be delivered by mixing wagons when its delivered you will be asked by the driver if you would like it wet or dry.

If you choose wet the concrete will take longer to set as the more water will be added choose dry and it will be poured as it arrives and will set in half the time.

For footings I would choose wet to very as the more time you have to lay the footings the better the finish will be able to achieve.

When the concrete gets poured into the trenches level it using a rake and then smooth the surface using a tamping batten.

tamping technique

The average time to complete the groundwork in my experience of self-build projects is approximately 1 week only a 1/3 more time than a hired team of ground workers.

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