Ten Things To Consider When Converting a Flat Roof to a Pitched Roof
|Our crews call this a "Frankenstein Roof"|
Flat roof with various sloped additions
and skylights with vents in wrong places.
February 7, 2014
Roofing Contractors Calgary, Red Deer, Edmonton, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Cranbrook, Kelowna, Vancouver, Whistler, and points between.
Every year about now, our phones start to ring about flat roof conversions and design options. Some homeowners ask us for advice about roof repairs and maintaining their flat roofs and get pro-active before the spring rains. Some inquirers want to build a deck on their flat roof to extend their outdoor living space. And others are done with the idea of a flat roof all together and want to convert their flat roof in to a sloped or pitched roof finishing it with shingles, shakes, tile, or whatnot.
1. A shingle roof is much less expensive than a flat roof. True or False?
A flat roof replacement is approximately two - three times more expensive than replacing shingles.
However, flat roofs typically last longer than shingles.
Shingle manufacturers now have "limited lifetime" warranties as the standard. When you review the wording of the warranty you find out what limited means.
Flat roof membranes are typically warrantied for ten or twenty years but if kept up will last up to forty years (in the right environment, with the right membrane and maintenance).
So yes, over-all or over a person's lifetime it is true that replacing shingles will likely be somewhat less expensive. A high end cedar shake a will be closer to a flat roof cost as will tile, metal, synthetic polymer's etc.
2. The cost to convert my flat roof to a sloped roof will be less than replacing my flat roof. True or False?
Usually the motivation for homeowners wanting to go from a flat roof to a pitched roof is driven by economics. Basically, the thinking goes something like this... if my flat roof costs x amount to replace or repair then why don't I simply make it a shingle roof because shingle roofs don't cost as much to replace and they don't leak as much.
Unfortunately, homeowners find early on in the process that the conversion process itself is cost prohibitive (relative to simply repairing or replacing the flat roof). A standard flat roof membrane replacement costs about 2 - 3 times that of a shingle replacement. That is true. However, to frame, replace the roofing material, insulate, install vapour barrier, soffits, fascia, gutters, siding, etc will typically be more costly than simply replacing the flat roof. In fact, the retro-fit cost could be 2 - 3 times the cost of simply replacing the flat roof.
Taking The Cheap Way Out
3. If I can't afford to replace my flat roof and I can't afford to retro-fit to a pitched roof correctly then why shouldn't I just add a simple cheap tin roof on top of my flat roof?
We see time and time again homeowners that have flat roofs that are failed (in other words they are soaked with moisture in the flat roof assembly) that have scab contractors erect hack framed tin roof structures on top of existing flat roofs. The reason this transpires is that the homeowner discovers the cost to replace the flat roof and begins to explore options. Then pricing comes in to retro-fit a pitched roof system properly and the home-owner discovers that is the same or much more than replacing the flat roof (depending on complexity or the renovation). And then the homeowner remembers, "hey, there was that one handyman that said if nothing else he could put up some simple framing and just put cheap tin on it". Yeah, that's the idea! I get a pitched roof, no more fussing with flat roof repairs and leaks, and it will be good enough I'm sure!
Unfortunately that's where the real nightmare begins and the "Frankenstein Roof" comes alive.
If the flat roof is completely failed and there is moisture in the roof assembly you will have mold eventually. The mold will spread. Also, the moisture itself will release depending on the weather etc. And finally, what about the framing and insulation in the roof assembly? It will of course likely be wet and moldy. All of which needs to be addressed.
Most times, when a homeowner opts to have a simple framed tin roof slapped up on their flat roof it is done by a handy person and the handy person typically has no idea how to address other issues such as how to fasten the trusses to the existing building with-out compromising the flat roof. And how to vent the flat roof and the new "tent" roof or how to insulate between the two for example. Or, what if the tin roof leaks? What if the tin roof condensates on the underside due to condensation from inadequate moisture and condensation?
Okay. So I Need to Do This Right, What Should I Consider?
4. Get the Right Team - Start with Hiring the Right Roofing ContractorRoofing contractors have different specialties - be sure the roofing contractor you choose is comfortable with this process. The best roofing contractors for the job will have a team that works together to bring all required trades together seamlessly.
5. Cross the T's and Dot the I's - Be Sure you Check with Local Building Codes and PermitsThe height of your house will be changing - be sure you secure correct permits well in advance of starting the process.
Get the right permits, be sure the roofing contractor knows what is required locally and what codes to follow.
Be sure any engineering required is done in advance of getting in to the project planning to far.
6. Resale Value - Consider Street Appeal and Value RetainedChanging your house to a pitched from a flat roof will change the architectural appeal or street appeal. Be sure you do not cause your home value to dip by choosing a design that buyer's won't like in the future. Consider the roof lines, siding, gutters, soffit, fascia, etc. Remember that one day your house will be sold.
If you are converting your roof to raise the value of your home, consider the value of your home will only increase about half of the original cost of the roof conversion (generally speaking). If you are selling your home within the next ten or so years, converting your flat roof to pitched may not be equitable.
7. My Flat Roof Isn't Structurally SoundA roof conversion from flat to pitched, if done properly, will succeed in distributing weight to the bearing walls of your home's structure. A roof conversion in this instance will transform a structurally unsound roof to a structurally sound dependable roof assembly.
8. Roof Efficiency is The Main Concern
|Ice Dams on the "Frankenstein" roof.|
It is more economical to insulate a pitched roof than it is to insulate a flat roof. Insulating the cavity of a flat roof assembly requires removing sheathing or insulating above the roof deck and below the roof membrane with rigid insulation, which is also costly.
9. More Storage RequiredIf storage is a motivating factor then a pitched roof attic will give you that advantage.
10. DesignDesign is a critical component to the renovation process. Be sure to take the time required with the roofing contractor, the person doing the drawings, and the engineer to be sure the design is one that will return the highest financial yield and yet be aesthetically pleasing for you.
I hope the ten points above help you with choosing to convert your flat roof or not to a pitched roof.
If you have any questions simply call or email us anytime at 1.877.497.3528 or firstname.lastname@example.org.
By +Tyler Sinclair - Staff Writer Google
General Roofing Systems Canada (GRS) | Calgary, Red Deer, Edmonton, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Cranbrook, Kelowna, Vancouver, Whistler, and points between.