With an emphasis on modular construction methods, SIPs construction has emerged as one of the more popular building systems. While it’s nothing new (SIPs have been around since the 50s), this method has remained relatively low-key until the past few years. Due to the sudden upturn in popularity, many have been left wondering whether SIPs are the next big thing in the construction industry or just another short-lived trend.
Like any other construction method, SIPs have their fair share of pros and cons. The key pros include energy efficiency, structural superiority, ease of construction, and eco-friendliness. The main cons include pest, moisture damage, and ventilation issues, as well as low fire resistance.
In the rest of this post, we’ll explore in detail the above (and many more) pros and cons of SIPs construction to help you decide whether this construction method is right for your next project.
But first, let’s define SIPs.
What Are SIPs?
SIPs stands for Structural Insulated Panel. It is a commercial and residential building system made of an insulating foam core pressed between two oriented strand board (OSB) facings.
Building with structural insulated panels can be advantageous in the following ways.
1. Energy Efficiency
Buildings with SIPs construction have great energy efficiency because this material is an excellent thermal insulator.
2. Insulating Foam Core
Being an excellent thermal insulator is largely due to the included insulating foam core, an airtight construction, and an energy-conserving ventilation system.
Since the foam core doesn’t conduct heat, it allows homes to retain warm air when it’s cold outside and prevents indoors from heating up during a scorcher. In doing so, it reduces reliance on HVAC systems for temperature control, which helps keep the electricity bill low.
3. Airtight Construction
As for the airtight construction, it helps maintain indoor temperature by minimizing the leakage of air into/out of interior spaces. With minimal thermal interference from the air outside, indoor air in SIPs buildings maintains the desired temperature for longer, which reduces the need for the AC.
Beyond that, the airtight construction can help minimize the passage of humidity from outside to your interiors to further ease the burden on your home’s HVAC system.
4. Unique Ventilation System
The unique ventilation system of SIPs buildings also plays an important role in energy conservation. Since SIPs are typically airtight, special attention must be accorded to ventilation in buildings with this kind of construction because adequate air circulation is critical to a healthy living space.
But since installing traditional ventilation systems would compromise the energy efficiency provided by SIPs’ airtightness, a specialized system known as Mechanical Ventilation with Heat Recovery (MVHR) is often used. MVHR systems operate 24/7, allowing fresh air to circulate through the building while also getting rid of pollutants and unwanted humidity.
But unlike traditional ventilation, MVHR systems allow air to circulate into and out of a building without losing heat that’s already been used in heating. Moist stale air from the interiors is taken through a heat exchanger that recovers the heat in it before being let out. The recovered heat is then transferred to incoming fresh air to pre-warm it before being circulated throughout the building.
With a high-efficiency heat exchanger, an MVHR system can recover up to 90% of the heat in outgoing stale air. This goes a long way to conserving energy, which translates to a lower electricity bill. And since the energy conservation mechanism of MVHR systems works both ways (i.e., it can help keep your interiors cool when it’s hot outside), it helps save money on heating costs all-year-round.
5. Design Versatility
Thanks to a combination of ease of connection and strength, SIPs give architects the flexibility to create unusual designs (such as sloping roof panels) that would otherwise be impossible with conventional building material like concrete, steel, or timber.
Such flexibility allows architects to express their design creativity without the restraints of conventional building materials, which comes in handy when elaborate building designs are desired.
6. Structural Superiority
SIPs structures can withstand harsh weather conditions and extreme climates because when complete, they form a monolithic shell that is seven times stronger than traditional timber frame structures. Beyond providing great structural strength, the monolithic shell gives buildings a solid and robust feel and makes them less susceptible to shifting.
7. Minimal Waste
Usually, SIPs are fabricated off-site (AKA in the factory). Since factory conditions are usually controlled to maximize operational efficiency, there’s little waste compared to on-site construction.
To further reduce the waste and minimize the environmental impact, some manufacturers go the extra mile of using panel offcuts to make spline connections while others recycle materials wherever possible.
Minimal waste isn’t just great for the environment; it also means a lower cost of construction waste disposal.
8. Room in Roof Option
One of the unique benefits of SIPs structures stems from the fact that they don’t need roof trusses. This means you have the option to convert the space under the roof into a habitable living space. So if you have a three-bedroom home, for instance, you can easily turn it into a five-bedroom house without having to construct another room.
9. Faster Project Completion
It’s faster to Build with SIPs than with traditional methods for several reasons. Among these is a high strength to weight ratio that allows builders to fit large sections of your house/office at once, significantly cutting down the project completion time.
Second is the fact that Structural Insulated Panels come prefabricated, pre-cut, and designated for the various walls and roofs of your structure. That means, unlike with other conventional construction methods, contractors won’t have to spend time preparing construction materials (e.g., mixing concrete, taking measurements, and so on). With less to be done, your project will take shorter to complete.
To put things into perspective, building a two-story 200m² house with SIPs typically takes about 3 days to prefabricate off-site and 10 days to put up on-site, bringing the whole project completion time to less than half a month. A brick house of the same size, on the other hand, may take three months or more depending on the contractor.
Also noteworthy is the fact that you can build with SIPs in all weather conditions. That means, unlike with some traditional construction methods such as brick, you won’t have to halt your project during inclement weather. With minimal weather interference, your project will run smoothly and subsequently take less time to complete.
Faster project completion is beneficial to homeowners because it means laborers will spend less time on-site, which helps reduce labor costs.
10. Minimal Construction Errors
SIPs come precision-engineered to fit the exact dimensions and design requirements of your project. This minimizes the chances of construction errors, and if any, they can easily be corrected before on-site erection.
11. Fewer Labor Requirements
Since SIPs structures are fabricated off-site, most of the construction is done back at the factory. As such, typical job site tasks such as framing and insulation installation won’t be part of your labor requirements.
SIPs panels are also delivered to the job site with door openings and pre-cut windows, meaning you won’t need to frame out openings on site. Additionally, SIPs structures don’t require bricklayers to build the inner leaf of a structure – a common process with conventional building systems.
Ultimately, SIPs construction is less labor-intensive than many, if not all, traditional construction methods.
12. Ease of Construction in Sites With Difficult Access
For homeowners with plots located in areas with limited access (such as near high traffic areas or plots bordering areas under conservation), building houses or offices using conventional methods can be quite a headache because construction machines like the concrete mixer may not be able to fit in your plot.
With SIPs construction, you won’t need as much heavy-duty equipment to build as you would when building with stone and timber. This means that your project will have minimal disruption to your surrounding environment, something that can’t be said for conventional construction systems.
Additionally, building with SIPs reduces construction material deliveries to your plot because everything comes from one source, meaning you won’t have to worry about traffic congestion. The means of delivery will also be specifically tailored to suit the size and access of your plot.
SIPs structures have great green credentials due to several reasons. First off, the foam insulation core in these panels has a low global warming potential and a zero Ozone Depletion Potential (ODP). Also, the great insulation it provides helps keep the energy consumption of buildings low, which is great for the environment.
Second, the exterior of structural insulated panels is made from Oriented Strand Board (OSB3), a material manufactured using fast-growing trees. Fast-growing trees have several environmental benefits, among them being a fast regeneration rate that helps reduce the environmental impact of using forest-derived products.Lastly, structural insulated panels use way less timber compared to traditional timber framing systems. This further bumps up the green credentials of SIPs by helping reduce the impact of deforestation on the environment.
14. Compatibility With Other Materials
Thanks to their design flexibility, SIPs can be used alongside other conventional construction materials. That means you can combine the panels with things like timber when building from scratch or simply add them to an existing building as enhancements.
Such compatibility comes in handy when building a large scale, where circumstances can sometimes prevent the property from being entirely built with SIPs.
15. Ease of Estimating Costs
Since SIPs structures come prefabricated, it’s easier to estimate the total cost of any given project. Everything is customized to each project’s specific dimensions and design requirements, making it easier to know beforehand how much of the material you’ll need so you can budget ahead.
16. Decent Soundproofing Properties
SIPs come with a unique layered structure, with panels having varying density. This structural makeup allows them to block out and absorb a wide spectrum of noise, making SIPs panels a decent material for soundproofing.
Keep in mind that the sound resistance of SIPs walls varies depending on the type of exterior finish applied, the thickness of the foam core, and the thickness of drywall applied (if any). Also, while SIPs are great at blocking high-frequency sound, they’re not as effective with low-frequency noise.
Having covered the main benefits of using SIPs in construction, let’s take a look at the disadvantages.
17. SIPs Structures Are Prone to Moisture Damage
One of the main disadvantages of SIPs buildings is that they are prone to moisture damage. This is mainly because the composition of SIPs panels includes wood, which is susceptible to rot, mildew, or mold.
However, you can get around this problem by installing a waterproof surface on your walls. Using heat ventilators to expel moist air in high humid areas such as kitchens and bathrooms may also help.
18. SIPs Panels May Harbor Pests
Most wood-based building systems are susceptible to pest issues in one way or another, and SIPs are no different. More often than not, termites pose the biggest threat to SIPs buildings. While these insects don’t feed on the material, they can hollow out the panels’ cores and use them as a nesting ground.
To prevent this, opt for SIPs with borate-treated OSB and/or foam. Many manufacturers are offering treated panels to address pest issues, so they won’t be hard to find. And even with treated panels, you’ll want to keep humidity well below 50% to keep pests and rodents at bay.
19. Ventilation May Be an Issue
While the airtightness of SIPs is great for insulation, it can compromise ventilation, especially in buildings made entirely of this material.
Poor ventilation can cause poor indoor air quality, increased humidity, accumulation of pollutants, and condensation on walls and windows. It can also lead to fire hazards in case of gas leaks and predispose building occupants to a host of medical conditions associated with poor indoor air quality.
Luckily, you can address ventilation issues in SIPs buildings by investing in an efficient mechanical ventilator. And since most conventional ventilators may compromise the energy efficiency of SIPs buildings, you’ll want to opt for a Mechanical Ventilation with Heat Recovery (MVHR) system. This way, you’ll air out your interior without sacrificing one of the biggest benefits of building with SIPs: insulation.
20. SIPs Leaves Little Room for Post-Build Improvements
While the off-site prefabrication of SIP structures speeds up construction, eliminates errors, and minimizes waste, it also limits how much you can alter your building after erection.
That’s because SIPs come precisely cut and customized to fit the CAD drawings of your building, and tampering with their design can compromise structural strength and efficiency. They also come with plumbing and wiring holes pre-drilled, making it difficult to run new electrical or plumbing lines after the building is erected.
Such limitations mean that you have to get your building’s design and features right during the planning phase. This is rarely the case because property owners’ needs often change with time, calling for structural tweaks.
Even if you don’t need to change the design and/or features of your building, chances are you’ll need to renovate several years down the line due to normal wear and tear caused by things like moisture or pest damage. Unfortunately, the possibilities in this regard are usually limited in SIPs buildings, and the few structural changes you can make will likely be costly.
22. Not Many Contractors Are Familiar With SIPs
SIPs construction is still relatively new, meaning only a handful of tradesmen have experience building with it. As such, it can take a while to find a skilled contractor, something that can stall your project.The shortage of skilled contractors in SIPs construction also means you can easily end up hiring a quack if you’re not careful with your selection process, which can leave you with a poorly constructed building. This can be costly, especially given that there isn’t much you can change in a SIPs building once it’s built.
23. SIPs Have Limited Fire Resistance
Another critical disadvantage of SIPs is that the Oriental Strand Board (OSB) and the composite structural material used to make the panels have a low fire performance rating.
While SIPs structures are often touted as fire-resistant, the panels only hold up well in flames when surrounded by another material with a good fire resistance rating such as drywall. That means if the drywall is faulty when a fire breaks out, occupants of your house would be at risk of smoke inhalation and burns.
24. SIPs Cost More Than Wood Framing
Building a small scale urban house with SIPs panels costs roughly 10% more than constructing a similarly sized house with wood framings. So while buildings made of this material may be more energy-efficient, eco-friendly, and faster to build, they’re likely to require a larger budget than wood.
The Bottom Line
As we’ve seen throughout this post, SIPs construction has several advantages over some of the conventional construction methods. And like any other construction material, it has its fair share of drawbacks.
But while the positives outweigh the negatives, the decision whether to build with SIPs will ultimately depend on your structural requirements, budget, and other individual-specific considerations.