London House Extension Builders:

Building homes for

happy families in London

mammoth design and builders in london

We do WOWLY designs + build for London property owners.

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We’re a London-based construction company specialising in design-led, bespoke, high-end homes for our clients

Faster. Smoother. Easier

A true turn-key solution

With Mammoth Build and Design, you can count on us to take care of every little detail from start to finish. From the point you decide to create your dream space, you can count on our teams to offer support in all the key areas including architectural plans, interior and exterior designs, estimating build costs, budgeting, planning permissions, project management and even construction in London. Our service offers true 360 support.

To see how our solutions could work for you, contact us today for an initial consultation.

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  1. PLANNING

Design & Build Company London

2. DESIGN DEVELOPMENT

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3. ESTIMATING BUDGETS

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4. CONSTRUCTION

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5. PROJECT MANAGEMENT

Our Key Services

Our team has over 100 years

of collective experience in:

Loft Conversions

Side Extensions

Garage Conversion

Rear Extensions

Interior Design

A step-by-step guide to building a new home…

house extension step by step process in london - mammoth builders
  • After choosing your extension type (rear, loft conversion, etc.), the next step is figuring out if you can build it without permission. There are two options:

    Permitted Development Rights (PDRs): These government-granted rights allow certain property modifications without needing a formal application.

    Planning Permission: This is approval from your local authority to proceed with your specific building plans. It's required if your extension doesn't qualify under PDRs.

    In simpler terms, PDRs are shortcuts that bypass the planning application process for specific extension types. If your project doesn't fit those categories, you'll need to go through the formal planning permission route.

  • We can connect you with a network of reputable architects who can handle both the planning permission process and building regulation compliance, making this stage smoother for you.

  • While an architect creates plans to ensure your extension meets building regulations, they typically focus on the structural aspects. To get a complete picture of your finished space, consider hiring an interior designer.

    A designer can craft detailed 2D and even 3D visuals of your extension, both inside and out. This will help you:

    See your dream come to life: Visualizations allow you to virtually walk through your extension and experience the space before construction begins.

    Make informed design choices: With a visual representation, you can experiment with different styles and finishes to find what works best for you.

    Stay on budget: Designers can advise on design choices that align with your budget, helping you avoid costly surprises later.

    In short, an architect ensures your extension is built to code, while a designer helps you design it to perfectly to suit your taste and budget.

  • While your design takes shape, it's crucial to establish a realistic budget for your project. Honesty is key: determine the maximum amount you're comfortable spending.

    Getting Accurate Quotes:

    To ensure your budget stays on track, we recommend seeking quotes from a design and build specialist. These professionals can provide a comprehensive breakdown of all construction costs, including:

    - Building materials (bricks, timber, etc.)

    - Labor costs

    - Interior finishes (kitchens, bathrooms, flooring)

    - Unexpected expenses (potential need for additional materials)

    By involving a design and build specialist early on, they can create your final plans with your budget in mind, minimizing the risk of cost overruns later.

    Once you finalise your budge source a list of reputable constructions firms who will be able to provide a detailed quotation for your intended works.

  • After choosing your contractor and approving their quote, the next step is to solidify your agreement with a formal contract. This document should clearly outline:

    Schedule of Works: A detailed breakdown of all construction stages, ensuring everyone's on the same page.

    Payment Plan: A transparent schedule for project payments, providing financial clarity.

    Project Timeline: A realistic timeframe for project completion, setting expectations.

    Starting Your Project:

    During the contract signing, discuss potential start dates with your contractor. Their availability will influence when your project can begin. By having a clear start date in the contract, you can plan accordingly and minimize delays.

  • Your project will need to comply with building regulations, which ensure your extension is safe and structurally sound. There are two ways to handle this:

    Local Council: You can utilize your local council's building control department. They will review your plans and inspect the construction at key stages to ensure compliance.

    Private Approved Inspector: Alternatively, you can hire a private approved inspector certified by the government. This can offer a more streamlined process in some cases.

    The Party Wall Act:

    If your extension involves shared walls or foundations with neighbouring properties, you'll need to follow the Party Wall Act. This act protects your neighbours and ensures clear communication about your project. Here's what you need to do:

    Party Wall Notice: You must serve a formal notice to your neighbours at least two months before construction begins. This notice outlines the planned work and protects your neighbours’ rights.

    By following these steps, you'll ensure your project adheres to all necessary regulations and maintains good relations with your neighbours.

  • Don't forget to update your home insurance! It's important to inform your provider about your planned extension work before construction begins. This ensures your coverage remains valid throughout the project.

  • Once construction commences, it's important to notify your chosen Building Control body (local council or private inspector). They'll then schedule inspections throughout the project to ensure everything is built according to your approved plans and adheres to building regulations.

    Think of Building Control as your partner in safety and compliance. They'll work closely with your contractors to verify that each construction stage meets the required standards, giving you peace of mind throughout the process.

  • During construction, clear communication with your contractor is key. Here's how to ensure a smooth process:

    Regular Updates: Schedule regular meetings or progress reports to stay informed about the project's status.

    Change Management: If there are any unexpected changes needed in the work or timeline, ensure both you and the contractor agree on them in writing. This avoids confusion and potential disputes later.

    Material Management: If your contract specifies that you'll provide certain materials, plan ahead! Order them well in advance to avoid delays due to late deliveries. We’re able to provide a complete “shopping list” of materials your project will require. We can even go one step further and ensure these are ordered in time and delivered as required.

    By following these tips, you can minimize stress and keep your project on track. Remember, a little proactive planning goes a long way in ensuring a successful extension.

  • Once construction wraps up, you'll need a final sign-off to ensure everything was built according to regulations. Here's the final step:

    Building Control Completion Certificate: Your chosen Building Control body (local council or private inspector) will issue a certificate once they've conducted a final inspection and confirmed everything meets compliance standards. This certificate signifies a successful project and is often required for various purposes, such as selling your property or registering your extension.

    Congratulations! With your completion certificate in hand, you can finally enjoy your beautiful new extension.

Have a question we haven't covered?

We’ve built our business on recommendations
from loyal clients…

Why choose us

✔️ A dedicated Account Manager to help you through the process

✔️ Keep your project on time & budget

✔️ Qualified and experienced team

☎️ Speak to an expert

Still not sure? Book a free 30-minute phone consultation and see how your project can come to life with Mammoth Design and Build.

E: hello@mammoth-builds.co.uk
M: 07878 719 909