TPO Roofing Contractor in Elgin & Kane County, IL

Heat-Welded Seams Are the Real Difference

TPO seams are welded with hot air rather than bonded with adhesive. A properly welded TPO seam is a homogeneous bond — the two sheets become one material — and it is typically stronger than the membrane either side of it.

That is a genuine advantage, and it is also where TPO installations go wrong. Weld temperature has to be right for the ambient conditions, and every weld should be probed. We probe seams as we go and we test-weld at the start of each day and after any significant temperature change. It is unglamorous and it is the whole job.

It also means TPO is less forgiving of a cheap crew than EPDM is. If you are comparing bids on a TPO roof, ask each contractor how they verify seam welds. The answers will tell you a lot.

Energy Performance on Chicago-Area Buildings

A white TPO membrane reflects the majority of solar radiation that a black roof absorbs. On a large-footprint building — a warehouse, a distribution center, a big-box retail unit — that shows up directly in summer cooling costs and in reduced load on rooftop units.

It also reduces thermal stress on the membrane and the deck, which is part of why TPO does well on the enormous roof areas typical of the Elk Grove Village and O'Hare industrial corridor.

The trade-off in a northern climate is that you lose some incidental winter solar gain. In practice the summer saving dominates on any building with meaningful air conditioning; on an unconditioned warehouse the calculation is closer and we will say so.

Insulation Is Not an Afterthought

On a low-slope roof, the insulation is most of the assembly's performance and most of its cost. Polyiso is the standard here, usually in two staggered layers so the joints do not line up and create thermal bridges.

Two things worth knowing as an owner. First, polyiso's R-value drops somewhat at low temperatures, which is exactly when you need it in Illinois — specifications should account for that rather than quoting the lab number. Second, tapered insulation is how you fix ponding on a flat deck, and it is the single most common thing missing from a cheap bid.

Ponding water is not merely cosmetic. Most manufacturer warranties, Carlisle's included, exclude damage from water that stands beyond a specified period. A roof that ponds is a roof with a warranty problem waiting to happen.

Re-Cover or Tear Off

TPO can sometimes be installed over an existing roof rather than tearing it off, which saves both money and business disruption. Whether that is appropriate depends on how many layers already exist, whether the existing insulation is dry, and what the structure can carry.

We take core samples before recommending a re-cover. A core tells you in ten minutes what a visual inspection cannot: how many layers are there, and whether the insulation is wet. Recovering over saturated insulation is the most expensive mistake available on a commercial roof, because you pay for the new roof and still have the old problem.