How Much Does it Cost to Build a House Extension

Building a house extension is an effectual way of creating more family living space, perhaps to accommodate an elderly relative or a growing family, or to give current home members more room.

It is often an economical option when compared to moving houses, not least due to finding the right area that meets your budget and purchasing process incurs estate agent and stamp duty fees. Not to mention the emotional aspect of such a life readjustment and the logistics of the removal – to pack your belongings, transport them, and unpack.

So, how much does it cost to build a house extension? Well, it depends as there are several variables in play – giving a definitive answer is really hard. We, therefore, decided to give you a compressive guide on how to do a house extension. Keep scrolling.


1. Pre-Building Costs Before Extending Your Home

Before adding your home, there are the costs and fees that are , involved. Note that not all costs will apply in your case, especially if you are redesigning an existing structure or your extension project is on a small scale.

· Design payments

An architect or registered building designer will be the specialist who will design your extension project. The fees payable will range from A$12 to A$18 – greatly based on experience.

· Interior design payments

If applicable, the costs depend on the master’s experience, A$ 72 to A$ 129 per hour.

· Drafts fees – A$6050 to A$9507

The draftsman will draw the plans based on the design. Note that the plans are submitted for council approval.

· An estimator or building surveyor – A$2592 to A$3313

You can consider approaching an independent building surveyor before you select the builders.

· Structural engineering costs

The estimated payments – A$2881 to A$4609

· Soil reports payments – A$432 to A$806

It is not always necessary – minus this cost to add an extension to the house.

· A land surveyor cost – A$1224 to A$5113

The well-detailed survey will depict the existing site features and structures, and the site boundaries. The local authorities have to approve it first before the building project starts.

· Planning permit & building regulations payments

They vary – depending on the type of work you would have done.


2. Do You Need Planning Permission to Extend Your House?

After getting plans drawn for an extension time, getting plans drawn up for an extension or simply getting plans for an extension, find out if you will need a planning permit. Addition or extension to your house is considered to be permitted development, subject to the below conditions and limits.

  • No raised platforms, balconies, or verandas.
  • Materials used to be similar to the existing house.
  • No side extensions
  • No cladding of the exterior
  • Upper-floor and side-facing windows to be 1.7m above the floor and be obscure-glazed.
  • The roof pitch of your extension should be higher than 1 storey to match the existing house.
  • The extension should not cover more than half of the land around the existing house.
  • The extension should not be higher than the highest part of the roof.
  • No extensions forward of the side elevation or principal elevation fronting a highway.


3. What is the Average Cost of a Home Extension?

what is the average cost of a house extension? Well, a number of factors play in the process making it extremely hard to estimate the cost. Here we have the essential cost variables and the overlookable expenses.

Essential cost variables

The general variables include:

  • Unusual terrain – Your workers will increase their cost to add extension to house if the soil type and the landscape at the site is making their work more difficult.
  • Builders waste removal – You will have to hire another company to clean up, another expense.cost to add extension to house add on home extension. Home renovation in Brisbane
  • The access to the property – Your workers will charge you more money if they are finding it a challenge to access the site and if they lack a convenient parking spot.
  • Construction overruns – It includes cost and time overruns.
  • Builders preliminaries – The firm will detail out a bill of quantities comprising the preliminary expenses.
  • Profit margin – Your builders want to gain or make a profit, their markup percentage is around 20 to 30%.
  • Size of the building company – Popular and large building firms will charge you more than smaller business.
  • Size of the project – The smaller and less complex, the less expensive the project will be and vice versa.

Overlookable expenses

They include:

  • Weather factors – bushfires, downpours, rain, or stormy conditions in the area will definitely incur unpredicted costs and delays.
  • Planning delays – Getting the right permits and approvals in time will incur unpredictable expenses.
  • Seasonal holidays and aspects – If the building project extends over the holidays, it may have an effect on the final cost.

4.  Any Other Costs to Consider

Below are common other costs to consider when planning to add on a home extension.

· Pipping & gas extension

What is the newly extended room for? If it’s a kitchen or a bathroom, you may require to install piping and gas. The planning, installation, design, and material costs will add to the final cost of the extension.

· Heating

To keep your extended space more comfortable, consider to factor in the cost of the insulation and HVAC, Heating, Ventilation, and air conditioning.

· Planning & building costs

There is no doubt that planning and building needs a lot of time and effort. Architects and designers carefully create the floor plan, you approve the plan, and the contractors begin to work on the project.

The process of adding your house will involve:

· Material cost

The quantity and quality of the materials used will have an effect on the final cost of extending your home project. For instance, if you use expensive and special materials, the cost will greatly increase.

Planning on building a house extension is not an easy task and can seem daunting. First, figure out the cost before everything else – having a rough idea of how much you will need to build your extension will make the project easier on you.

Rokco Builds can help with adding your house! For more details, Reach them via their main site now.

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