How to build a timber porch

Building a porch roof not only enhances the curb appeal of your home but also provides a shaded retreat and protection from the weather. This step-by-step guide will help you design, plan, and construct a porch roof that complements your home's architecture and lasts for years. Whether you're a seasoned DIY enthusiast or a motivated beginner, these instructions, coupled with a careful approach, will ensure your project's success.

Initial Planning Steps

Before starting any building works, careful planning is crucial. Here are the primary steps you should take:

Assess the Existing Structure: If you have an existing porch inspect it to ensure that it can support a new roof based on its current construction. This might involve checking the foundations and existing columns for structural integrity.

Determine the Roof / Porch Type: Decide on the type of roof or porch you want—gable, hip, shed, or flat. Each type has different structural requirements and aesthetic impacts.

Design the Porch / Roof: Create a design that matches your home’s existing roof in terms of pitch, materials, and style. Use software or consult with a professional if necessary.

Materials List: Compile a list of materials based on your design. You'll typically need beams, rafters, roofing material, flashing, guttering, and perhaps plywood or osb sheathing.

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Budget and Schedule: Estimate the cost of materials and any tools you may need to rent or buy. Plan a schedule and take into consideration that weather delays and other potential interruptions may arise during the build.

Building Your Porch Roof: Step-by-Step Guide

Step 1: Install Support Beams

Your porch roof will need sturdy support beams to hold up the roof structure. These beams will rest on the top of the porch's columns. Ensure that the beams are level and securely attached. If your porch lacks columns, you may need to install them as well, ensuring they are anchored properly into the ground and that they support the weight of the roof.

Step 2: Attach Rafters

Rafters form the skeleton of your roof structure. Space them according to local building codes and the specifications of your roofing material. Attach the rafters to the support beams using high wind / hurricane ties for additional stability. The angle at which you cut the rafters will depend on the pitch of your roof.

Step 3: Lay Roof Decking

If your roof design calls for it, lay plywood or OSB decking over the rafters to provide a base for your roofing material. Secure the decking with nails or screws, making sure to achieve a smooth, solid surface.

Step 4: Install Roofing Material

Choose a roofing material that matches your home and fits your budget. Common choices include asphalt shingles, metal roofing, or tiles. Start from the bottom edge of the roof and work your way up, overlapping materials as required by the manufacturer's guidelines.

Step 5: Add Flashing and Waterproofing

Install flashing around any areas where leaks might occur, such as where the porch roof meets the house. Apply a waterproof membrane or roofing felt before installing the roofing material if required by your specific type of roof.

Step 6: Install Gutters and Downpipes

Attaching gutters and downpipes will help direct rainwater away from your porch and the foundation of your house. Ensure they are securely attached and that water flows freely, without pooling.

Step 7: Finishing Touches

Inspect your roof for any gaps or potential leak spots. Apply caulk or sealant where necessary. You might also want to paint or finish exposed wood to match your home’s exterior and to provide additional weather protection.


Building a new porch / roof is a rewarding project that can enhance your home’s functionality and aesthetic appeal. By following these steps and adhering to local building codes, you’ll create a durable and attractive porch roof. Remember, safety is paramount, so take appropriate precautions during construction.

You can browse from the broad range of timber, sheet materials and more in the Harlow Timber Online Store HERE