What Insulation Do I Need For A Garage Renovation?

We’ve said it before, but transforming your garage into liveable space is one of the best and most affordable ways to increase your home’s square footage. The biggest obstacle will be transforming the damp, freezing garage into a comfortable living space. Insulation is a vital component of this change.

Parking spaces are not meant for human habitation. Their sole function is to protect your vehicle from the elements. Your automobile doesn’t mind the wet and cold of your garage, but you certainly do.

The local building codes should be checked before any materials are purchased. Converting a garage into a dwelling space definitely requires adhering to certain regulations. Get the suggested R-value for the walls, ceiling, and floor, too. The R-value of insulation measures how well it keeps heat in.

Roofs and Walls

Look for gaps in the ceiling and walls that could allow water to seep in. Prior to proceeding, these holes must be patched. Spray foam can be used for this purpose.

Insulate the space between the studs in the walls and the ceiling joists using fibreglass batt insulation. Insulate the space, but don’t pack it too tightly. To maximise its effectiveness, face insulation’s vapour barrier should be oriented such that it faces you, the source of heat. Approximately every 8 inches, staple the flanges to the studs.

First, check that the concrete floor is level and dry.

To insulate a garage, you can either lay down a layer of rigid foam insulation or set up wood sleepers and sandwich rigid foam panels in between them.

A vapour barrier should be used. Put in place polythene with a thickness of six millimetres (plastic sheeting). Use enough to cover the entire slab and then some (4–6 inches) up the walls. Use insulating tape to seal the seam and make it overlap by about 8 inches. Place the foam board over the plastic sheeting, leaving a 1/4-inch gap all around the edges if sleepers are not being used. Insulation tape can be used to seal off the cracks.

For the sleepers, go for a 1-by-4 or 2-by-4 that won’t attract insects or rot. Line the outside of the garage with sleepers. Space the sleepers out from the walls by a quarter of an inch. Fill in the remaining space; if working with 1-by-4s, arrange the boards so their centres are 12 inches apart.

Suggested spacing for 2-by-4 sleeper stock is 16 inches. Nail the sleepers down to the concrete with a powder-operated nailer. Using 2-by-4 sleepers will yield a significantly more robust floor.

It is recommended that the rigid foam insulation be the same depth as the sleepers. Put the foam in the space in between the beds, but leave a quarter-inch border around the outside. The only acceptable rigid foam insulation panels are those that can withstand compression.

FAQs About Garage Renovation

How Much Does It Cost To Insulate A Garage?

The options for insulating are to treat the internal or external surface. The advantages of external insulation are that it retains more of the floor space and, most importantly, provides weather-proofing to the wall. 

Starting price for insulation materials will be around $350 for sufficient polystyrene and fixings for a single garage, plus installation costs which will be significant. That will provide 50mm polystyrene, which will need to be clad or rendered to provide a waterproof finish. 

While there is potential for the skilled DIYer to take on the project, it is not simple and probably best left to the professionals. In which case, budget $100/m2 for the finished project.  

Do I Need To Insulate A Garage?

The method and amount of insulation will vary with the intended use for the garage. If it is to be used for a garage conversion idea such as a utility room or home gym, say, it will need less insolation than if it is to be used as a living space or a bedroom. In the first case, the 50mm insulation discussed above would be adequate. 

If it is to be used for accommodation, it would be wise to increase to at least 70mm Kingspan or Celotex or 100mm polystyrene. 

It is not uncommon for the garage to be repurposed, at least in part, as a plant room to accommodate a boiler or heat pump and hot water cylinder, perhaps with solar panel control gear. 

In this case, insulation is not necessary. However, consideration might be given to pipe runs from and around the garage to ensure they are not in the way if there is a change of mind and the garage is to be used as accommodation. 

Is Insulating A Garage Worth It?

If the garage is being converted to accommodation space, there is no option. It will be necessary to comply with building regulations and be sufficiently comfortable to live in. 

In financial terms, the questions of ‘payback’ or ‘return on investment’ do not occur. The project is extending the living space and will therefore add to the heating bill. Insulating the garage will minimise that and improve the thermal comfort of the garage and any adjacent rooms, but it will not reduce the overall heating bill.

What Insulation Do I Need For The Garage?

Fibreglass is the most commonly used type of insulation in garages (just as it’s the most popular type in homes). It’s sold in precut batts and long blankets that fit between wall studs and ceiling joists.

What Is The Cheapest Way To Insulate A Garage?

Fibreglass roll insulation is the cheapest and easiest type to install, provided that your garage’s interior walls have not been constructed. Unroll the insulation between the wall studs with the vapour barrier facing the inside of the garage.

Insulate The Walls, Ceiling And Floor

It is usually simpler to insulate a garage than it is to insulate a house. However, you can’t properly insulate the garage without first understanding its structure and why insulation is necessary.

It is not your primary goal to maintain a comfortable temperature in the garage; rather, you want to insulate the home from the garage if the temperature in the bedroom above it (or the living room next to it) is too low.

However, the same level of insulation as the house itself is required for a garage that has been converted into living space, whether it is attached or detached.

What follows are the essential details of the procedure.

Garage Walls

Most garage walls are made of single-layer brick or block, making them vulnerable to water seepage during rainstorms. In an unheated garage, any moisture that makes it through the walls will likely evaporate before it becomes a problem.

When insulation is added to a wall, air cannot circulate, and condensation can no longer be prevented from forming within. Poor brickwork or pointing, cracks in the render, failing gutters, and the like can all lead to a moist interior wall surface and should be addressed before insulation is added.

To insulate, you can either treat the inside or the outside. The most significant benefit of external wall insulation is its ability to keep the interior dry and comfortable regardless of the weather.

Nonetheless, it is more common for insulation to be installed on the inside of the walls because this method is typically easier and cheaper. We may accomplish this in three different ways.

Fix The Insulation Directly To The Wall

Products from Kingspan and Celotex, which feature insulation that is glued to plasterboard and a vapour barrier, are made with this strategy in mind. If the wall’s surface is in good shape, this might be a fast and cheap way to add insulation.

As well as mechanical fasteners, the boards are affixed to the wall by being attached to it with a specialised adhesive (screws). Installation is quick, offsetting the high cost of the boards, which range from £9/m2 for Tektherm polystyrene to £19/m2 for Celotex PL4040.

Fix Battens To The Wall Which Can Carry The Insulation

As a result, any moisture that makes its way through the wall will be prevented from reaching the insulation thanks to the space between the two.

This technique also works well in cases where the wall is extremely skewed. Since the materials are the same, the price is comparable to the first way, plus the price of battens.

Construct A New Stud Wall Inside The Existing Wall

Since this is the most costly method without any noticeable improvement in efficacy, it is often only done when the current wall is especially vulnerable to rainfall penetration. Since stud walls are typically 100 mm thick and require a 40 mm ventilated cavity between them and the wall, they will take up a lot of valuable real estate on the ground level.

Apply Insulating Plaster Directly To The Internal Wall

Natural insulation, such as a hemp or cork-lime mix (the hemp or cork supplying the insulation) or layers of lime plaster sandwiching a cork or wood fibre insulation, is ideal for stone walls due to their breathability.

Although this choice will not provide a low U-value (typically around 0.5W/m2, which is about the same as 50mm polystyrene will do), it does provide a solid fixing for pictures, cabinets, etc., is breathable, and deals with moisture penetration, so it is a viable alternative to the more expensive alternatives.

The goal is to maintain a comfortable temperature in the rooms above or adjacent to the garage. Only the party wall connecting one room to the next needs to be insulated. Since it is a hollow wall, the cavity space must be stuffed with insulation first.

Since the exterior wall surface is protected from the outdoors, there is no risk of moisture intrusion. An additional layer of insulation might be added to the exterior of the wall, but since the wall is already protected, the cavity fill should be adequate.

Converting an integral garage into liveable space often necessitates cavity-filling the walls. The cavity in this wall needs to be filled in order for exterior insulation to be effective.

Insulate The Roof/Ceiling

When insulating a roof or ceiling, the same guidelines apply as when insulating any other similar space in a home. It may be necessary to remove an old ceiling and insulate the space between the joists in a flat roof. Installing insulation between rafters on a pitched roof creates a ventilation space between the insulation and the roof’s underside. Rigid foam insulation is probably the most user-friendly and efficient option in both scenarios.

It is possible to batten over the joists or rafters to keep the insulation in place, or to reinstall the plasterboards to create a ceiling. Similar to the walls in terms of price and U-value.

Insulate A Garage Floor

In all likelihood, the floor is made of uninsulated concrete that was set above a hardcore. Fixing the garage floor is essential to making the space usable, even only to satisfy code enforcement. To instal insulation would require digging up the floor and relaying the concrete, which is an expensive proposition. A more workable solution is to insulate the floor, the thickness of which will depend on the height of the ceiling. To achieve a U-value of 0.22W/m2K, the ideal insulation thickness is 100mm of rigid foam insulation. To be considered liveable, a room must have a ceiling height of at least 2.1m. It’s possible that the ceiling is too low to accommodate 100 mm of insulation, or that it causes issues elsewhere, such as around door thresholds. In that situation, set up as much as you can. If adding 10mm of insulation to a floor does not significantly reduce the U-value, at least the floor will feel warmer.

Insulate A Garage Door 

It is preferable to remove the door and replace it with an insulated timber frame or masonry wall if the garage is to be converted into a living space.

Specific materials, such as ThermaWrap, Superfoil, or Weather Stop, are available if it has to be kept as vehicle access and insulation is still required. Installing them is an easy DIY project that costs roughly $60 for a single garage door and involves glueing them to the inside of the door using self-adhesive or adhesive pads.

Sealing strips and draught excluders like Weather Stop (among others) are another easy $50 DIY project that will help keep the cold air out. Treating the garage door in this way will make the garage a warmer, more welcoming place without significantly increasing the cost of construction.

Garage Conversion Insulation Requirements

How much insulation must be installed on the walls, floor, and ceiling of a converted garage is governed by local and national building codes. U-values are commonly used as a metric for assessing insulation effectiveness. The amount of heat that escapes from your home or building is indicated by the U-values. Watts-Per-Square-Kilowatt-Hour (W/m2K) is the unit of measurement used to determine U-values.

Insulation requirements for a garage conversion, as specified by building codes, include U-values as low as:

• 0.18 W/m2K for a flat roof
• 0.28 W/m2K for the walls
• 0.22 W/m2K for the floor

The garage conversion minimum floor insulation depends on the material that you use. The most common form of insulation is polystyrene, which would need to be 100mm thick.

5 Types Of Insulation For Your Garage

If you intend to heat your garage, insulation is a must. Garage insulation can be the same as that used everywhere in the house, but the degree to which it needs to perform may need a change in the type of insulation employed. The garage door, which must be insulated in a different way than the walls and ceiling, should also be considered.

Consider these five options for garage insulation.

Fibreglass Insulation

When it comes to insulating a garage, fibreglass is by far the most common choice (just as it is in residential settings). You may insulate the voids in your walls and ceiling using precut batts or long blankets. Another option is to purchase loose-fill fibreglass insulation and blow it into the space above the completed ceiling of your garage.

If the walls and ceiling are going to be exposed to the elements, you should insulate them using paper-faced or encapsulated fibre glass batts, which are wrapped in plastic (not covered with drywall or plywood). These will hide the unpleasant insulation fibres and give the walls a more finished look.

Cellulose Insulation

Cellulose insulation, sometimes known as loose-fill insulation, is becoming increasingly popular. Cellulose is often manufactured from recycled newspapers and treated with a fire retardant before being blown into wall and ceiling cavities using a specialised blowing equipment. If you buy your cellulose from a hardware store, they may lend you a blower for free, and you may also rent blowers from a number of other tool rental companies.

Due to its loose-fill nature, cellulose is best suited for use on completed garage walls and ceilings. If the garage is finished but lacks insulation, it may be remedied by cutting holes in the wall material at appropriate spots, spraying the insulating substance into the spaces between the frame parts, and then patching up the holes.

Insulation using Rigid Foam

Rigid foam typically comes in 4′ by 8′ sheets with thicknesses ranging from 1/2 inch to 4 inches. Styrofoam-like expanded polystyrene, polyisocyanurate extrusions, and extruded polystyrene are some of the most common materials utilised. Rigid foam is excellent insulation material and can be cut to almost any size or form. Take use of it as an insulator for garage doors and paper-thin walls.

Insulation Spray Foam

Spray foam is the best option if you want to insulate your property and keep out draughts (above and beyond the low-expanding canned solution). Since spray foam is an expensive premium material often reserved for energy-efficient construction, it may be overkill for most garage makeovers. On the other hand, this may be a sensible move if you want to convert the garage into a living area.

Sealing and Insulating Garage Doors

Don’t overlook the big door while installing garage insulation. For the most popular types of metal garage doors, you can buy prefabricated insulation kits, or you can buy rigid foam insulation or Reflectix sheets and cut them to size.

You should know that the metal ribbing that gives the garage door its structural integrity is a powerful heat conductor and is almost never insulated. Because of this, the door’s overall thermal performance will fall far short of what is advertised for the insulation.

Sealant designed to prevent air leakage is ideal for use on garage doors. Using weather stripping garage door trim will provide a watertight seal throughout the door’s perimeter and at its peak. Put a new rubber gasket at the door’s base to replace the old seal. It’s available in several dimensions to suit a range of clearance heights for garage doors.

Garage Insulation Basics

Installing a garage heater, whether it be permanent or temporary, requires insulation. There is no purpose in insulating if you aren’t also heating the space. One common misperception is that insulation makes a space warmer.

Insulation is beneficial in both warm and cold areas because it reduces the rate at which heat escapes through uninsulated walls, ceilings, and floors.

Some people think that adding insulation to the walls of an unheated garage attached to a house can help create a thermal barrier between the house and the outside.

However, there is no jurisdiction that mandates whole garage insulation as part of energy efficiency standards.

2 It’s also quite doubtful that the savings made from this marginal increase in energy transfer would be enough to justify the expenses incurred by installing such thick layers of insulation. But it’s important to always insulate to the utmost value the walls that touch the house.

Conclusion

Insulation is a vital component of transforming a garage into a living space. Look for gaps in the ceiling and walls that could allow water to seep in. Insulate the space between the studs in the walls and the ceiling joists using fibreglass batt insulation. The R-value of insulation measures how well it keeps heat in. The most significant benefit of external wall insulation is its ability to keep the interior dry and comfortable.

Poor brickwork or pointing, cracks in the render, failing gutters, and the like can all lead to moist interior wall surfaces. Fix Battens To The Wall Which Can Carry The Insulation. As well as mechanical fasteners, the boards are affixed to the wall by being attached to it with a specialised adhesive (screws) This technique also works well in cases where the wall is extremely skewed. Since the materials are the same, the price is comparable to the first way, plus the price of battens. Installing insulation between rafters on a pitched roof creates a ventilation space between the insulation and the roof’s underside.

Rigid foam insulation is probably the most user-friendly and efficient option in both scenarios. To achieve a U-value of 0.22W/m2K, the ideal insulation thickness is 100mm of rigid foam insulation. Insulation for a converted garage is governed by local and national building codes. Most common form of insulation is polystyrene, which would need to be 100mm thick. Insulation requirements for a garage conversion include U-values as low as 0.18 W/m2K for a flat roof.

Cellulose insulation, sometimes known as loose-fill insulation, is becoming increasingly popular. Cellulose is often manufactured from recycled newspapers and treated with a fire retardant before being blown into wall and ceiling cavities. Spray foam is the best option if you want to insulate your property and keep out draughts. Insulation is beneficial in both warm and cold areas because it reduces the rate at which heat escapes through uninsulated walls, ceilings, and floors. There is no jurisdiction that mandates whole garage insulation as part of energy efficiency standards. But it’s important to always insulate to the utmost value the walls that touch the house.

Content Summary

1. We’ve said it before, but transforming your garage into liveable space is one of the best and most affordable ways to increase your home’s square footage.
2. The biggest obstacle will be transforming the damp, freezing garage into a comfortable living space.
3. Insulation is a vital component of this change.
4. Their sole function is to protect your vehicle from the elements.
5. Your automobile doesn’t mind the wet and cold of your garage, but you certainly do.
6. Converting a garage into a dwelling space definitely requires adhering to certain regulations.
7. Get the suggested R-value for the walls, ceiling, and floor, too.
8. Insulate the space between the studs in the walls and the ceiling joists using fibreglass batt insulation.
9. Insulate the space, but don’t pack it too tightly.
10. To insulate a garage, you can either lay down a layer of rigid foam insulation or set up wood sleepers and sandwich rigid foam panels in between them.
11. Nail the sleepers down to the concrete with a powder-operated nailer.
12. Using 2-by-4 sleepers will yield a significantly more robust floor.
13. It is recommended that the rigid foam insulation be the same depth as the sleepers.
14. The only acceptable rigid foam insulation panels are those that can withstand compression.
15. Insulate The Walls, Ceiling And FloorIt is usually simpler to insulate a garage than it is to insulate a house.
16. However, you can’t properly insulate the garage without first understanding its structure and why insulation is necessary.
17. However, the same level of insulation as the house itself is required for a garage that has been converted into living space, whether it is attached or detached.
18. What follows are the essential details of the procedure.
19. To insulate, you can either treat the inside or the outside.
20. The most significant benefit of external wall insulation is its ability to keep the interior dry and comfortable regardless of the weather.
21. Nonetheless, it is more common for insulation to be installed on the inside of the walls because this method is typically easier and cheaper.
22. Fix The Insulation Directly To The WallProducts from Kingspan and Celotex, which feature insulation that is glued to plasterboard and a vapour barrier, are made with this strategy in mind.
23. As well as mechanical fasteners, the boards are affixed to the wall by being attached to it with a specialised adhesive (screws).
24. Installation is quick, offsetting the high cost of the boards, which range from £9/m2 for Tektherm polystyrene to £19/m2 for Celotex PL4040.Fix Battens To The Wall Which Can Carry The InsulationAs a result, any moisture that makes its way through the wall will be prevented from reaching the insulation thanks to the space between the two.
25. This technique also works well in cases where the wall is extremely skewed.
26. Construct A New Stud Wall Inside The Existing WallSince this is the most costly method without any noticeable improvement in efficacy, it is often only done when the current wall is especially vulnerable to rainfall penetration.
27. Since stud walls are typically 100 mm thick and require a 40 mm ventilated cavity between them and the wall, they will take up a lot of valuable real estate on the ground level.
28. Apply Insulating Plaster Directly To The Internal WallNatural insulation, such as a hemp or cork-lime mix (the hemp or cork supplying the insulation) or layers of lime plaster sandwiching a cork or wood fibre insulation, is ideal for stone walls due to their breathability.
29. The goal is to maintain a comfortable temperature in the rooms above or adjacent to the garage.
30. Only the party wall connecting one room to the next needs to be insulated.
31. Since it is a hollow wall, the cavity space must be stuffed with insulation first.
32. An additional layer of insulation might be added to the exterior of the wall, but since the wall is already protected, the cavity fill should be adequate.
33. When insulating a roof or ceiling, the same guidelines apply as when insulating any other similar space in a home.
34. It may be necessary to remove an old ceiling and insulate the space between the joists in a flat roof.
35. Installing insulation between rafters on a pitched roof creates a ventilation space between the insulation and the roof’s underside.
36. It is possible to batten over the joists or rafters to keep the insulation in place, or to reinstall the plasterboards to create a ceiling.
37. Similar to the walls in terms of price and U-value.
38. Insulate A Garage FloorIn all likelihood, the floor is made of uninsulated concrete that was set above a hardcore.
39. Fixing the garage floor is essential to making the space usable, even only to satisfy code enforcement.
40. A more workable solution is to insulate the floor, the thickness of which will depend on the height of the ceiling.
41. Insulate A Garage Door It is preferable to remove the door and replace it with an insulated timber frame or masonry wall if the garage is to be converted into a living space.
42. Treating the garage door in this way will make the garage a warmer, more welcoming place without significantly increasing the cost of construction.
43. Garage Conversion Insulation RequirementsHow much insulation must be installed on the walls, floor, and ceiling of a converted garage is governed by local and national building codes.
44. The amount of heat that escapes from your home or building is indicated by the U-values.
45. The garage door, which must be insulated in a different way than the walls and ceiling, should also be considered.
46. Consider these five options for garage insulation.
47. You may insulate the voids in your walls and ceiling using precut batts or long blankets.
48. Another option is to purchase loose-fill fibreglass insulation and blow it into the space above the completed ceiling of your garage.
49. Cellulose insulation, sometimes known as loose-fill insulation, is becoming increasingly popular.
50. Due to its loose-fill nature, cellulose is best suited for use on completed garage walls and ceilings.
51. Rigid foam is excellent insulation material and can be cut to almost any size or form.
52. Take use of it as an insulator for garage doors and paper-thin walls.
53. Sealing and Insulating Garage DoorsDon’t overlook the big door while installing garage insulation.
54. For the most popular types of metal garage doors, you can buy prefabricated insulation kits, or you can buy rigid foam insulation or Reflectix sheets and cut them to size.
55. You should know that the metal ribbing that gives the garage door its structural integrity is a powerful heat conductor and is almost never insulated.
56. Because of this, the door’s overall thermal performance will fall far short of what is advertised for the insulation.
57. Sealant designed to prevent air leakage is ideal for use on garage doors.
58. Using weather stripping garage door trim will provide a watertight seal throughout the door’s perimeter and at its peak.
59. Put a new rubber gasket at the door’s base to replace the old seal.
60. It’s available in several dimensions to suit a range of clearance heights for garage doors.
61. Garage Insulation BasicsInstalling a garage heater, whether it be permanent or temporary, requires insulation.
62. There is no purpose in insulating if you aren’t also heating the space.
63. One common misperception is that insulation makes a space warmer.
64. Some people think that adding insulation to the walls of an unheated garage attached to a house can help create a thermal barrier between the house and the outside.
65. However, there is no jurisdiction that mandates whole garage insulation as part of energy efficiency standards.2 It’s also quite doubtful that the savings made from this marginal increase in energy transfer would be enough to justify the expenses incurred by installing such thick layers of insulation.
66. But it’s important to always insulate to the utmost value the walls that touch the house.