Instant Cost Calculator

Please fill in the form below for an instant online quotation. All fields marked * are required.

Width (metres)
Length (metres)
Your quick quote below
Permissions in place
Building Control
Roof Type
Kitchen Required
Open Plan
Move Drains
Windows
Doors
Flooring
Architect Drawings
Velux Windows
Heating Type
Bathrooms
En-suite
Wet Room
Digger Access
Timescale

Nearly there just a few more clicks to view your quote and have it emailed to you.

Name
Telephone
Postcode
BOOK A FREE 30 MINUTE SURVEY AND GET 20% OFF YOUR QUOTE!

Summer Sizzle!

No Deposit this Summer

30 minutes Surveyor Visit

Free, No Obligation.

Bi-fold Doors

50% off entire range

Free Velux Roof Vent

A breath of fresh air.

Building a Double Storey house extension is always a very exciting project and often too consuming for a lot of builders but not here at Space Extension where we specialise in Double storey extensions. There are some key factors you have to consider.

Step 1

  • Where are you looking to place the extension.
  • Is it possible to build the extension where you would like it located.
  • Is there a better option that will mean less preparation such as moving drains etc.
  • Will an extension put value on to your property.
  • What is the value of your property, e.g. it doesn’t make sense to put a £60k extension onto a property that’s worth £115k. You would be better moving home!

Step 2

  • What permissions are required. You will nearly always require planning permission to build a double storey extension to your property.
  • How much will an architect cost. This depends on the size of the extension but allow for roughly £1500
  • How should I set my budget? Take the value of your property and divide this amount by the total number of rooms in the house, lounge, kitchen and bathrooms etc. This gives you the average cost of a room in your property this is a good starting budget then add on any extras such as kitchen, bi-fold doors, wet rooms etc.
  • What other hidden costs are there? Building Regs’ are roughly £700, Planning permissions are roughly £250.

Step 3

  • Design of the extension. Option 1 contemporary so it is modern and allows you to get creative with the design or Option 2 brick match, window match and roof match so the extension looks like its always been there and the property has never been extended.
  • Internal extras. Read our kitchen extension link to work out the cost of a kitchen on top of the extension cost.
  • Most builders quotes, and most prices quoted online, are for what we call a shell. This simply means the extension is finished to building regulations but does not include any extras such as flooring, decoration, kitchens or specialised lighting etc.
  • Problems always arise when your budget for your extension is low and you expect all the extras to fall within that budget as well.
  • Always ask your builder for price freeze to ensure the price agreed is all you pay.
  • Ensure your builder offers you whats called a full scope of works. This should be done electronically and allow you to electronically sign it and return so you both have proof of what is or is not included to avoid any issues further down the line.