Q&A Forums

Removing Existing Roof Post New Topic | Post Reply

Author Comments
Trey Gibson
Posted: Feb 17, 2009 08:14 AM
Removing Existing Roof
What is the typical charge for removing an existing roof? The particular one I have in mind looks like a tar roof with pebbles on top of it. This client is interested in retrofitting his many buildings with foam roofs but the existing has to be removed first.
Posted: Feb 17, 2009 01:12 PM
It really depends on the scope of work that needs to be done.

Just removing rocks can get up to $1.00 per sq. ft and I strongly suggest a Vacuum Truck if it is a big Job that way you don't have to deal with getting rid of the gravel. They don't pack well in driveways, so keep that in mind if you plan on having a use for them.

If you have to remove tar, etc..., you really have to figure your labor, time, etc... in order to get the job done and then put your markup on it.

Once you do a tear off, you will ultimatly have to replace some decking if water has penetrated over a long period of time, which brings up the cost even more.

Overall, just do your homework in advance, take core plug samples to see how many roofs you are dealing with and make it worth your wild.

I have done more than one roof where I underestimate the tear offs, but quoted the foam right and ended up spending a week on a 2-3 day job.

Also, keep in mind once you tear off that roof and are not ready to foam because of what you find under the roof, you have to deal with the weather while making repairs before spraying foam.

I jumped around the subject a little bit, so I am not sure if that was helpful or not.

richard sucher II
Posted: Feb 19, 2009 01:43 PM
have been spraying foam and doing commercial EPDM roofing systems for several years. When estimating the cost of tear-off, you need to core cut the roof to see what type of roofing material you have, how many roof systems you have and how wet the roof material is. Landfill costs are very high so you need to calculate the weight of thematerial that you are removing. There is insulation, felt plies, asphalt inner ply moppings and asphalt top coat with pea gravel as well as dirt and debris.
Tear off by hand is very hard. If you have any size at all, you need to get power equipment such as roof cutters. You cannot cut several layers of roofing at once; you may have to cut, tear off, cut and tear off until you get to the deck.
Be aware of presence of asbestos and also pay attention to "coal tar pitch" roofing material. This material can "burn" your employees if you do not take precautions to protect them from "pitch" burns.
Metal decking materials, if the deck needs repairing, is very hard to find at a minutes notice for small quantities. Also, it is hard to match new decking material to existing decking. Some of the older styles are not available.
What I am saying is do your homework so that you can anticipate these issues. Good luck.
Dennis Davidson
Posted: Mar 13, 2009 01:31 PM
Taking a core sample is a MUST!!! There can be as many as three roof systems on a building. Don't get caught in a trap! Unless you core down to the deck it could cost you plenty. I just walked away from a job last week because the customer refused to let me take a core. So..what's he hiding? I think he's waiting for some poor hungry contractor to come along?
The best way to approach a tear-off is to do it in sections - tear-off, spray back and base coat. On a roof with two roof systems and wet insulation we usually do about 5,000 sq. ft. per day.
Good Luck!
Posted: Mar 14, 2009 11:18 PM
Is it pretty universal that no more than two roofs can be applied at any one time. We did a complete tear off in the New Orleans French Quarter a few months ago and the building inspector actually wrote up the building owners for have a total of four roofs built one on top of the other.

I was surprised that there were 4 different types of roofs to begin with, but even more surprised that they wrote the building owners up.


You need to login to reply to this topic. Please click here to login.