Rooflines on an older home with an addition
Older homes are often beautiful. Additions onto those older homes can also be beautiful. But reroofing can bring out some not-so-beautiful facts: different materials, different slopes and pitches, and odd angles where the addition roof meets the original roof.
Roof Transitions Are the Main Design Problem
On older steeply-pitched roofs with a lower pitched addition, it’s important to carefully plan for transitions from the steeper pitch to the lower pitch, and where the material may change. (Some products work well on steeply-pitched roofs but not on lower pitched areas where drainage is slower.) This will require more detailed planning:
- where valleys are, and how wide to make them
- how and in what direction various flashings will overlap
- whether you’ll install diverters, additional gutters or other details to control the increased amounts of water flowing off the steeply pitched roofs, especially during high-wind rainstorms
- how to deal with movement and expansion/contraction at the transition from dissimilar roofing materials
Rain, wind and sun conspire to get inside wherever the roof is weakest. Different planes, valleys, intersections with sidewalls, and especially transitions all need careful thought and detailed drawings before your new roof is built.
Strengthening the Roof From the Deck Up
Roof decking and flashing details
Tearing off the existing roofing product will reveal the roof deck. At this point it’s important to walk the entire roof to see if there are soft spots, cracks, separations, and other evidence of deterioration. It may be cheaper now to replace bad deck boards instead of later on when a leak works it loose.
It’s also important at this point to check how well the deck is attached to the structural roof framing and, where feasible and within budget, beef up the connections so the roof better resists high winds.
- Deck properly attached to structure
- Seams in deck properly flashed
- Underlayment suited to the slope of each roof plane
- Flashing where roof planes intersect
- Flashing where chimneys and other items penetrate the roof
- Flashing where the roof intersects sidewalls
- Carefully secured edges and eaves, to resist peeling back in high winds
- Properly balanced and unobstructed ventilation, for fresh air coming in the soffits/eaves and for old air to leave at ridge/high points
Depending on what work will be done, check with the local building department to see if a permit or approvals (Wikipedia’s version at www.en.wikipedia.org/wiki/Building_permit is the least fluffy) will be required before tear off starts and before materials are ordered. Permits are often required when the structural framing is being modified or when the pitch and shape of the roof is being changed.
What Happens Inside the Attic?
It’s a good time to re-inspect the attic, while the crew is working on your roof. Additions are sometimes built without adequate ventilation. Bathroom or kitchen fans might blow warm moist air directly into the attic instead of venting to the outdoors. Insulation might be blowing against the soffit/eave vent openings and blocking the free flow of air.
Look in each cavity to see if daylight shines through the roof deck seams, if the wood framing looks blackened or weathered, if the insulation looks damp, if there are any musty/mold-like growths – but how does FORTIFIED reroofing planning for Uptown New Orleans homes account for what you find?
Preserving Character and Preparing for Work
There’s no need to repeat old mistakes when your reroof project reveals them. It may turn out that, in the past:
- different thickness decking was used
- the rafters/trusses/joists are spaced differently
- the roof on the addition ends at the siding on the original house, rather than properly overlapping the shingles, as it should
- flashing was once installed, then covered over when trim boards or siding were added later
- more than one layer of roof covering is being torn off
- there may be no attic venting in the addition.
The good news is that with careful planning, all these problems can be corrected while still preserving the original trim, materials and rooflines that give the house its distinctive character and charm.
Take lots of pictures!
Before the old roof comes off, it can be helpful to take pictures of the rooflines, from ground level and also from the roof itself. Close-up shots where one roof plane meets another, of valleys and flashings and other details can be a help later, when new materials and new flashings are properly rebuilt without repeating past shortcuts.
Define what work will be done
Before the old roof comes off, make sure there is a clear scope of work defined for any repairs needed, and agree on it before the new roof is started. Decide who will replace or install:
- Damaged decking
- Flashing where chimneys or other items penetrate the roof
- Flashing where one roof plane meets another
- Flashing where the roof intersects sidewalls
- Gutter systems, or other changes to control rainwater where steeply pitched original roofs drain directly onto the lower pitched addition
Walk the job site
It can also be helpful before tear-off starts to walk the property with the person in charge of the crew, and point out:
- attic hatches, for easy access to attic
- outdoor electric outlets, that may get bumped or disconnected during the work
- areas to pile tree limbs, roof tear-off, etc., that the hauling truck can pickup
- delicate or prize gardens/plants/trees
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