Recommendations from builders on how to properly make a pitched roof on a garage yourself

Although it may seem impossible, building a pitched roof for your garage is completely doable with the correct advice. In addition to improving the appearance of your garage, a well-built roof shields your possessions from the weather. Pitching a roof is a worthwhile project, whether your goal is to increase the value of your home or just make your garage more functional.

In this post, we’ll provide helpful advice from seasoned builders to assist you in building a pitched garage roof. From planning and preparation through the actual construction process, we’ll go over all the important steps. You’ll be able to approach the project with accuracy and confidence if you follow these tips.

Since safety is the most important factor in any construction project, we’ll also go over some key safety precautions you should take. By adhering to these professional advice, you can guarantee that your pitched roof is long-lasting, strong, and resilient. Together, we will take on the task of giving your garage a new pitched roof.

Types of roofs

Pitch roofs in garages are most commonly found on wooden rafter systems and reinforced concrete floor slabs. The reinforced concrete slabs serve as the box’s roof and ceiling if the rafters’ structure is understood to imply the existence of an attic. Each design has benefits and drawbacks of its own.

Three types of roofs are used to build a garage’s pitched roof:

  1. Sliding system assumes that the lower ends of the rafters can slide freely across the support beams (mauerlat). This is done in garages made of timber or logs, which are subject to significant shrinkage. Beams are laid at a slope due to the difference in heights of opposite walls. The movable lower part of the roof absorbs deformations of the garage walls, thereby preserving itself from destruction.
  2. Hanging system rafters are a structure that is not rigidly connected to the walls. The roof consists of a series of trusses in the form of right triangles, where the hypotenuse is the rafters, the vertical leg is the pediment of the wall or pillars, covered with sheet material. They are connected by a rafter beam.
  3. Tilt system used when the walls of the box are built from cinder blocks, foam blocks, precast reinforced concrete or brick. The base of the roof is reinforced concrete floor slabs, the slope of which is formed due to the difference in heights of opposite walls.

If you adhere to these professional advice, building a pitched roof on a garage yourself can be a satisfying project: To keep your garage weatherproof, start with a well-thought-out plan, select high-quality materials, double-check measurements and angles, and pay special attention to ventilation and waterproofing.

Design features and calculations

A pitched roof’s rafter system is made up of a number of parallel, angled wooden beams. The sheathing used to lay the roofing is made from the rafters themselves.

Roof design foundation computations comprise of parameters like:

  • angle of inclination and its direction;
  • shape and design of rafters;
  • cross-section and length of load-bearing beams;
  • complexity of truss design;
  • thermal insulation.

Angle of inclination and its direction

The slope roofs get steeper with increasing angle. We calculate its minimum value based on SNiP 2.01.07-85*. Determine the maximum snow load at the box’s construction site and the wind direction by using the map and table provided.

Determine the ideal roof slope in the related table using this data. In order to allow the force of the air masses to press the roof downward, the direction of the roof slope is chosen to align with the prevailing winds.

Furthermore, the slope of the roof should allow snow to melt quickly and match a specific kind of roofing:

  • from 10 to 200 – profiled sheeting;
  • more than 200 – slate, ondulin, natural tiles;
  • from 250 – metal tiles.

Shape and design of rafters

Three types of wood are used to make rafters, purlins, support beams, sleepers, and braces:

  1. Solid timber.
  2. Logs.
  3. Glued laminated timber.

Solid timber

Wood is used for purlin elements and rafter construction. The most common material used to install roofing systems is this one.

A beam that has a cross-section of at least 50 x 150 mm is highly load-bearing, able to support the weight of coatings made of the heaviest materials as well as the maximum loads caused by wind and snow.

Logs

Occasionally, logs are used to construct the garage roof’s supporting structure. To achieve this, 15 to 20 centimeter tree trunks are used, their bark removed, and antiseptics applied.

Glued laminated timber

In the factory, it is created by gluing separate boards together to form a single monolith.

Although the material can support more weight, it becomes "afraid" of higher humidity levels. These rafters will be more expensive than logs and solid timber beams.

The location of the vehicle entry and exit points from the box is protected from precipitation by extended rafters with roofing coverings if the high portion of the roof is situated above the garage door.

Section and length of load-bearing beams

A garage box’s standard dimensions are 3 by 6 meters. Depending on the length of the overhangs, the length of the rafters, if laid in a long direction, will be between 6.2 and 6.5 meters. The rafters are frequently positioned parallel to the box gate’s plane. After that, beams between 3.2 and 3.4 meters long are created.

Together with the other components, the supporting beam that is longer than six meters creates a truss, a frame support structure. Regarding the load-bearing beams’ cross-section, 50 x 150 mm solid or glued beams or 150 mm logs will do for span lengths up to 3.5 meters (including overhangs). I use logs Ø 200 mm or timber with a section of 50 x 200 mm for lengths of six meters or more.

Complexity of truss design

One or two extra spacers are inserted inside the frame of a truss, which sets it apart from a basic rafter system (rafter legs). Their purpose is to reduce the rafters’ span as much as feasible. We refer to these rafter systems as hanging.

The figure below displays different approaches to truss design solutions. The figure’s lower fragment displays a schematic of a garage’s roofing that spans 12 to 16 meters. These types of garages are constructed for businesses that look after their own fleet of automobiles.

Thermal insulation

If the box is going to be heated, it makes sense to insulate the roof. Install different types of boilers, electric heaters, or run pipes from the home boiler to radiators in order to achieve this. In any event, insulation of the ceiling, walls, and floor is necessary to maintain heat within the garage.

The best way to insulate a pitched roof with a rafter system from heat is to place roll insulation between the floor beams and cover it with OSB sheets or boards.

The widths of the roll insulation material are 1 m and 1.2 m, so the pitch between the beams is kept at this measurement along the axes. When installed, the insulation fills the space completely and leaves no gaps. Three layers of 50 mm thick thermal insulation mats are layered on top of one another.

In the second scenario, roof insulation is completed as follows when the garage’s shed roof is made of reinforced concrete slabs arranged at an angle on walls with varying heights:

  • Along the perimeter of the roof, sides with a height of 150 – 200 mm are installed. This may be a continuation of the masonry walls or special panels made of sheet material;
  • the dry surface of the slabs is cleaned of dirt and debris;
  • covered with film vapor barrier;
  • everything is covered with expanded clay 100 – 150 mm thick;
  • the backfill is compacted using improvised means;
  • a screed of cement mortar of a grade of at least M 150 and a thickness of 50 mm is made on top;
  • the screed is covered with a soft roof on bitumen mastic.

Tools and materials

Toolkits and materials are required for the installation of the garage roof truss system.

Instruments:

  • circular and miter saw;
  • jigsaw;
  • wood saw;
  • hammer, axe;
  • electric drill and screwdriver;
  • tape measure, laser level;
  • marker.

Resources:

  • solid or glued timber;
  • boards;
  • plywood or OSB sheets;
  • roll waterproofing;
  • roofing felt;
  • liquid antiseptic;
  • hardware (bolts, nuts, screws, self-tapping screws, nails);
  • metal mounting angles.

DIY construction instructions

Two options for roofing need to be taken into consideration: building an extension box and a pitched roof for a separate garage.

How to build a detached garage with a pitched roof, step-by-step instructions:

  1. Depending on the conditions of the soil foundation, a strip or column foundation is erected.
  2. Arrange the grillage by pouring the formwork with reinforced frames.
  3. Walls made of brick, cinder blocks or foam blocks are erected simultaneously with the installation of gates.
  4. Inside, a concrete floor screed is made on a sand-crushed stone cushion.
  5. A support beam (mauerlat) is laid on top of the opposite two walls, covered with roofing felt, which is secured to the masonry with studs.
  6. Floor beams are supported on the Mauerlat, securing them with screws or nails.
  7. The beams are hemmed underneath with plywood or OSB sheets using a screwdriver.
  8. The ceiling is covered with a vapor barrier (plastic film).
  9. The space between the beams is filled with insulation.
  10. On the one hand, vertical racks are installed on the wall, fastening them with hardware to the mauerlat, followed by cladding of the pediment.
  11. The top of the posts and the opposite ends of the beams are connected together by rafters, creating a series of trusses.
  12. A sheathing of boards is installed on top of the rafters.
  13. The sheathing is covered with rolled waterproofing.
  14. Install the roofing covering (corrugated sheeting, bitumen tiles, natural tiles, ondulin, metal tiles, etc.P.).

Here are detailed instructions for building a garage box extension with a pitched roof:

  1. A foundation is erected for the extension, separate from the base of the house.
  2. External walls along with gates are erected from different materials (brick, cinder block, etc.).
  3. The adjacent side of the garage, depending on the layout of the house, can be built in any acceptable design, providing the partition with an entrance door.
  4. The roof slopes towards the gate. The rear side of the extension roof is brought under the roof overhangs of the main building.

Here are some video instructions to help you build a pitched garage roof yourself:

Tip Details
Plan Ahead Start by planning your roof design carefully. Consider the size of your garage and the type of roof that will best suit your needs and climate.
Gather Materials Make sure you have all the necessary materials before starting. This includes roofing sheets, timber for the frame, nails, and any other hardware.
Build a Strong Frame The frame supports the entire roof, so ensure it’s sturdy and well-built. Use quality timber and secure it properly with nails or screws.
Install Roofing Sheets Lay the roofing sheets from the bottom to the top, overlapping each row to ensure proper water runoff. Make sure they are secured tightly to prevent leaks.
Check for Leaks Once the roof is installed, check for any gaps or leaks. Seal any problem areas with roofing sealant to keep the garage dry.
Maintain Regularly Inspect your roof regularly for any signs of damage or wear. Keeping it in good condition will prolong its lifespan.

You can build a pitched roof on your garage yourself if you have the right equipment and instructions. Plan ahead, measure precisely, and select high-quality materials first. This base makes sure that your project is ready for success right from the start.

To guarantee stability and efficient water drainage, keep in mind to firmly install the rafters and maintain the correct angles when building the frame. Your garage will be weatherproofed if you use strong roofing materials and a waterproof underlayment.

Don’t undervalue the significance of insulation and ventilation. Insulation helps control the temperature inside the garage, preventing moisture buildup and enhancing its year-round functionality.

Finally, safety ought to come first at all times. Employ the proper safety equipment, use ladders according to best practices, and don’t be afraid to ask for assistance if a task seems too difficult. You can have an effective and long-lasting pitched roof for your garage with perseverance and careful attention to detail.

Video on the topic

Construction of a pitched roof

Armopoyas on a lean-to garage.

Do-it-yourself SINGLE ROOF for a GARAGE in one person

What factor is most important for you when choosing materials for building a house??
Share to friends
Milan Yashina

Design engineer, specialist in development of design documentation. I will help you correctly design your home or other building.

Rate author
StroyArsenal62.com
Add a comment