New framing
Studs at consistent centres, no finishes in the way, and every bay visible for inspection before drywall. This is the condition batts were designed for.
Service
Fibreglass Batt Insulation in Mississauga
Pre-cut fibreglass batts fitted into walls, ceilings, basements and garages — in houses, commercial spaces and new construction across Mississauga and the GTA.
- What it does
- Fills a regular cavity economically, when fitted well
- Where it goes
- Walls, ceilings, floors, basements and garages
- Depends on
- Fit — compression and gaps cost real performance
- Cost driver
- Area, cavity depth, access and the amount of cutting
Fibreglass batt insulation is pre-cut lengths of spun glass fibre friction-fitted between studs, joists or rafters. It remains the most cost-effective choice for regular, accessible framing, and its performance depends almost entirely on being cut and fitted without compression or gaps.
What fibreglass batts are
Fibreglass batts are made from spun glass fibres formed into flexible blankets, supplied in widths matched to standard framing spacing and in a range of thicknesses. They are friction-fitted into the cavity — pushed in so they hold themselves in place, filling it edge to edge and front to back.
It is the oldest and most familiar insulation in Canadian construction, and it has a reputation problem that is mostly undeserved. Batts do not underperform because fibreglass is a poor insulator. They underperform because they are quick to install badly, and a batt stuffed around a wire or squashed behind a pipe stops doing what the label says.
Note on spelling: we use fibreglass, the Canadian spelling. You will see fiberglass on American product literature. Same material.
Where batts are used
Walls
Exterior walls in new construction and in renovations where the framing is open. Interior partition walls where the goal is sound control between rooms.
Ceilings and floors
Ceilings below unheated attics where the framing suits batts, floors over unheated garages and crawl spaces, and floors between units in multi-unit buildings.
Basements
Framed basement walls, usually as part of a finishing project. The assembly needs care here — a basement wall has to be able to dry, and the arrangement of insulation and vapour control on a below-grade wall matters more than in an above-grade one.
Garages
Garage walls shared with living space, and garage ceilings where there is a room above. The cantilevered or garage-adjacent bedroom is the most common cold-room complaint we hear.
New construction
This is where batts are at their best: open framing, regular spacing, clear access, and a crew that can work through it systematically. Most of the volume we install for builders and general contractors is batt.
Commercial spaces
Demising walls between tenancies, office partitions, ceiling plenums and mechanical room walls in commercial buildings.
Why fitting is everything
The performance figure on a batt is measured on a batt at its full loft, filling the space completely. Every departure from that in the field reduces what you actually get.
Independent research on installed insulation has consistently found large gaps between rated and delivered performance in poorly fitted batt installations. That is not an argument against batts — it is an argument for installing them properly, which takes longer than stuffing them in and is why quotes differ.
What proper batt installation looks like
- Batt fills the cavity fully — top to bottom, edge to edge, front to back
- Cut to length for short bays rather than folded over
- Split around wiring and pipes, not compressed behind them
- Cut precisely around outlet boxes rather than crushed around them
- Narrow bays get a batt cut to width, not a full batt jammed in
- No gaps at the top plate, bottom plate or against the studs
- Insulation held in place so it does not slump before the wall is closed
Compression, gaps and obstructions
Compression reduces thickness, and thickness is where the thermal resistance comes from. A batt squashed into a shallower cavity does not deliver its rated value. Where a cavity is shallower than the batt is thick, the answer is a batt sized for the cavity — not a thicker one forced in.
Gaps matter more than their size suggests. A small gap allows air to circulate within the cavity, and convection moves far more heat than conduction through the surrounding insulation. A wall that is 95% perfectly insulated and 5% gap does not perform at 95%.
Obstructions — wiring, plumbing, bracing, boxes — are where batt installations are won or lost. The correct technique is to split the batt through its thickness and pass the obstruction between the two halves, so there is insulation both in front of and behind it. The fast technique is to squash the whole batt behind the pipe, leaving the cavity in front of it empty. The two look identical once the drywall is up.
Thermal performance
Batts are rated by thermal resistance, and the value you can achieve in a given wall is limited by how deep the cavity is. That is the main constraint: in a shallow assembly, you cannot get more performance by choosing a better batt beyond a point — you run out of depth.
Two things affect the real-world result beyond the rated value:
- Air sealing. Batts do not stop air movement. An assembly with batts and no air barrier leaks. This is why batts belong with a properly detailed air barrier, and why in some applications — rim joists especially — foam earns its cost by doing both jobs at once.
- Thermal bridging. The framing itself conducts heat around the insulation. This is a property of the assembly, not the batt, and it is why continuous exterior insulation is specified on many newer assemblies.
We do not publish specific R-value targets on this page, because the required values depend on the assembly, the building type and the applicable code edition. We confirm what applies to your project and quote to it.
Sound control
Fibreglass in a cavity absorbs airborne sound travelling through that cavity, which reduces how much passes from one side to the other. That is genuinely useful in partition walls between bedrooms, around home offices, in party walls and between floors.
What it does not do is soundproof a room. Sound isolation is a property of the whole assembly — the mass of the layers, whether the two sides are structurally connected, and how well the perimeter is sealed. Insulation contributes; it is not the mechanism. Our soundproofing page explains the difference between absorption and isolation properly, because conflating the two is how people end up disappointed.
Fibreglass vs. spray foam
| Fibreglass batts | Spray foam | |
|---|---|---|
| Cost | Significantly lower | Higher |
| Air sealing | No — needs a separate air barrier | Yes, at sufficient thickness |
| Irregular cavities | Requires careful cutting; easy to get wrong | Conforms automatically |
| Thermal resistance per inch | Lower | Higher, especially closed-cell |
| Sensitivity to workmanship | High | Lower for fit; still needs correct thickness |
| Later access to the cavity | Easy — batts can be pulled and replaced | Difficult — foam is bonded in place |
| Disruption during install | Minimal | Area must be vacated and ventilated |
| Best in | Open, regular, accessible framing | Irregular cavities, rim joists, where air sealing matters most |
On many projects the sensible answer is both: foam where it earns its cost — rim joists, cantilevers, awkward corners — and batts through the regular framing.
The installation process
- Review. We look at the framing, cavity depths, obstructions and what the assembly needs to achieve.
- Quote. Material, thickness, area, and any vapour control or air sealing included in the scope.
- Delivery and staging. Material staged so it is not being dragged through finished areas.
- Installation. Batts cut to fit each bay, split around obstructions, fitted without compression.
- Vapour control and air sealing where it is in scope.
- Inspection. A walk of the work before it is covered — which is the only time anyone can see it.
- Clean-up. Offcuts and packaging removed.
What affects the cost
- Area — square footage of wall, ceiling or floor
- Thickness and product — higher-performance batts cost more per square foot
- Framing regularity — standard spacing is quick; irregular framing, odd angles and short bays take much longer
- Obstructions — heavily serviced walls take longer to do properly
- Access and staging — height, floor level, and how material reaches the work area
- Vapour control and air sealing if included
- New build vs. retrofit — open framing is far quicker than working in a finished building
- Site conditions — occupied buildings and phased access add time
Frequently asked questions
Is fibreglass insulation still a good choice?
Yes, in the right assembly. In an open, regular, accessible stud cavity that has been air sealed separately, correctly fitted fibreglass batts deliver their specified thermal performance at a fraction of the cost of foam. The material is not the weak point — poor installation is.
Why do we use "fibreglass" rather than "fiberglass"?
Fibreglass is the Canadian and British spelling; fiberglass is the American one. They refer to the same material. We use the Canadian spelling because we work in Ontario.
Do fibreglass batts need a vapour barrier?
Batts on their own do not control vapour movement, so assemblies that need vapour control get it from a separate layer — a poly sheet, a kraft facing or another approved material — installed on the appropriate side. Which arrangement applies depends on the assembly and the applicable building code, and we confirm it for your project before installing.
Can batts be installed over existing insulation?
In an attic, unfaced batts can sometimes be laid over existing insulation, but it is awkward to do well and easy to compress what is underneath. Blown-in loose-fill is usually the better choice for topping up an attic floor. In walls, adding batts on top of existing insulation is rarely practical.
Does fibreglass insulation soundproof a room?
It helps, but it does not soundproof on its own. Batts in a wall cavity absorb airborne sound travelling through that cavity, which reduces transmission. Genuine sound isolation depends on the whole assembly — the layers, the framing and the sealing — not on the insulation alone. Our soundproofing page explains the difference.
Do you supply the material as well as installing it?
Yes. Quotes are for supply and install unless you specifically want to supply your own material, in which case tell us at quoting stage.
Applications
Where batts are the sensible answer
In a clean, square, accessible cavity a correctly fitted batt is efficient and economical. That is a real category, and it covers a great deal of ordinary construction.
Interior partitions
Between bedrooms, around home offices and either side of a shared corridor, batts add useful absorption within the cavity at a modest cost.
Basement walls
On a framed and strapped foundation wall, batts insulate the finished space — provided the moisture strategy behind the framing has been settled first.
Garage ceilings
Living space above an unheated garage, where the joist bays are regular and fully accessible from below before the ceiling goes on.
Floor assemblies
Between storeys, mainly for sound rather than heat, and over unheated spaces such as porches and cantilevers where the bay is straightforward.
Mixed-material projects
Foam where the assembly demands it, batts everywhere the cavity is simple. Using one material for the whole building is a habit, not a specification.
Suitability
Where fibreglass batt insulation does and does not belong
Every material on this site is the wrong answer somewhere. Knowing which side of this split your project sits on is worth more than any specification sheet.
A good fit when
- Square, regular, unobstructed stud and joist bays
- Open framing where every bay can be inspected before it is closed
- Projects where budget matters and the cavity does not need sealing
- Interior walls and floors where absorption is the acoustic goal
Probably the wrong choice when
- Irregular framing, or cavities crossed by pipes, wiring and ducts
- Anywhere the assembly needs an air seal as part of the insulation
- Attic floors with uneven joist spacing — loose fill covers those better
- Damp or unresolved-moisture locations where the cause has not been fixed
If your project sits on the right-hand list, say so when you call and we will point you at the service that actually fits — including the cheaper one. Here is how this work relates to everything else we do.
Batts and foam are constantly presented as rivals, which misses the point: they answer different questions. Where a cavity is irregular, obstructed or needs sealing as well as insulating, spray foam is worth its premium. Where an attic floor simply needs depth, blown-in loose fill covers around joists and wiring in a way batts never manage. Plenty of buildings are best served by using more than one.
Batts also carry a real acoustic benefit inside a partition, though absorption within a cavity is only part of the story — proper sound-control work has to account for the structural paths around it. For a broader comparison of the three common materials, choosing insulation for a Mississauga home is the guide to read.
Batt work spans everything we do: basements and garages in houses, partitions and demising walls in commercial fit-outs, and whole subdivisions for builders working to a specification. We install across the GTA, including Concord and Brampton. If you want a straight comparison against foam for your particular assembly, send us the details.
Before you commit
Why two identical batts perform differently
Batts are the most commonly mis-installed insulation in the trade, and every failure mode is invisible fifteen minutes after the drywall arrives.
Compressed to fit
A batt squashed into a shallower cavity than it was made for loses much of what you paid for. The batt has to match the depth of the bay, not be forced into it.
Cut short or gapped
Small gaps at the top, bottom or sides of a bay let air circulate around the insulation entirely. A neat, full-height friction fit is the whole job.
Stuffed around obstructions
Wiring and pipes should be split around, not compressed behind. Packing a batt in front of a cable leaves a void behind it and a compressed section in front.
Treated as an air barrier
Fibreglass does not stop air movement. Where an assembly needs both, the air sealing is a separate step and needs to be specified and paid for as one.
Also from NorthStar
Other services that come up alongside this one
Fireproofing
Spray-applied cementitious fire-resistive material and intumescent coatings for structural steel in commercial and industrial buildings.
Soundproofing
Acoustic treatment for walls, ceilings and mechanical rooms in homes, offices and multi-unit buildings, planned around how sound actually travels.
Spray Foam Insulation
Open-cell and closed-cell polyurethane foam that insulates and air seals in a single application. Used in attics, walls, basements, crawl spaces and commercial envelopes.
Related services and reading
Get a quote for fibreglass batt insulation
Send us the drawings or describe the space. We will quote supply and install, and tell you where a different product would serve you better.