When it comes to insulating low-slope residential roofs, it’s important to do it right and to ensure longevity for the installation. For the most part, these roofs are gently sloping, mostly flat, or completely flat. And in terms of construction, these roofs come in a wide variety – some with attic space, others with very little. Without getting too technical, this is insulation work that must be done correctly – with proper sealing to make the space airtight and with appropriate ventilation.
Insulation contractors usually deal with the inadequacies of a roof before insulation is installed. In general, roofs leak air, and attics suffer from poor ventilation – both these conditions require retrofitting to make sure that installed insulation will perform. Failing to seal tight and properly ventilate will set the stage for undesirable moisture throughout the space, affecting performance levels of insulation. Building code or not, the space should be made as airtight as possible.
Cutting corners by not installing proper ventilation in a low-slope roof is a prescription for future problems. In fact, moisture can be the biggest enemy – from saturating the existing insulation, to compromising R-Values, to creating a home for mold. All of this considered, it’s better to install an insulation “system” correctly the first time, rather than risk roof damage that might require re-construction. Simply put, a good “system” comprises sealing, insulation and ventilation.
For some insulation specialists, low slope roofs are ideal for applying spray polyurethane foam. It’s an application that seals the space airtight; blocks unwanted air leakage; prevents moisture collection; and provides thermal insulation – all at one time. Along with appropriate ventilation, most every building inspector will be satisfied with the results. At the same time, this is clearly not a DIY project – there are just too many moving parts for the uninitiated to manage.
Professional insulation contractors understand the full extent of insulating a low slope residential roof. They understand moisture dynamics – they understand the capacity of different products to perform – and they understand the importance of code-compliant ventilation. Quite importantly, they also know what to do when repairs and retrofitting are required prior to the installation of any insulation. Indeed, this may be a good scenario, since starting from scratch has benefits.
With highly specialized projects like low slope roofs, installers must be highly qualified, with the capacity to work collaboratively with other trades. This is especially true when retrofitting is part of the overall project work. Working in any other way will compromise the quality of the project, while risking the performance of the installed insulation. Simply put, effectively insulating low-slope roofs will depend wholly on the experience and expertise of a professional approach.
As for product options, whether the installation specifies blown insulation, batt insulation or spray foam, a quality approach is recommended. This includes following applicable building codes, installing everything according to manufacturer specifications, and doing it all right the first time around – it will simply guarantee the best in short term and long term outcomes.