Is it better to remove the old roof?

Steve S · #1 08-20-2010, 09:03 PM

We are going to have our 19 year roof replaced because of leaks.. We have had several bids and the lowest, told us that we don't need to remove the old roof. He will just add on to it.

The other roofers want to remove the old roof not knowing how the wood underneath looks after two decades of minor leaks. They can replace it if needed.

Which way should we go?

Dirk Diggler · #2 08-20-2010, 09:08 PM

Remove it, no doubt if you've had leaks over the years the wood underneath will be punky and no good.

But if money is an issue then a re-roof will hold you most likely for another 20 years if there are no more leaks.

Your call, I used to do roofing many years ago and things have actually changed for the better in roofing technology. You might even consider a metal roof, we did recently and other than our in attic antennae no longer working it's been great. Oh and we put the metal right over the existing asphalt shingles.

Dirk

FF Petro · #3 08-20-2010, 09:37 PM

With only 3/4" plywood and especially OSB you can tell pretty well if you have any rotten spots from underneath. It would only take a few minutes of inspecting from your attic.

Also, it's not code in many places to reshingle over architectural shingles. They weigh a lot more.

As long as you don't have architectural shingles and the decking still looks good there is no reason you would have to remove the old roof.

T-Bird · #4 08-21-2010, 12:51 AM

Hi.

In addition to what the others have said, be sure to check whether the support structure will take the additional weight of the new roofing material. You don't list Your location, but on snowy parts of the world, taking the snow load into account will in most cases probhibit leaving the old roof below the new one.

If this was my house or one that I'm renovating, I'd make the calculations and check the structure. Only then would I make the desicion. But, I live in a part of the world which puts quite a bit of demand to the building methods as well as design.

Regards
Sam

The_Ox · #5 08-21-2010, 01:24 AM

I re-roofed my house with my old man about 2 1/2 years back; and all I have to say is
(aside from tearing off the old roof; the funnest part btw), get tips from a pro first, we wasted at least two days doing it wrong; and our ex-roofer neighbor showed us a more efficient way of doing it. But hey, I gained an Epiphone Thunderbird out of my hard work.

Steve S · #6 08-21-2010, 04:43 AM

Thanks for the suggestions. I've learned a lot that will help me with the decision. I live in the Pacific NW and it does get damp over here.

iamlowsound · #7 08-21-2010, 06:23 AM

I used to roof, I say remove the old ones. It is a much better way of doing it. With roofers, make sure that you get references and NEVER pay in cash.

lowsound

Jonyak · #8 08-21-2010, 08:02 AM

I pad a friend cash to do my roof, he is a part time roofer. His crew did a great job.

if you live in a cold climate make sure to get them to lay down ice shield which is a rubberized membrane, and not just tar paper. I beleive code is 3 feet od tar paper. we got them to do 9 feet of ice shield and then the rest on tar paper. the roof should hold up for a long time.

also get them to remoe the old shingles that way you can find any problem areas r mistakes that were made by the old roofers.

JimB52 · #9 08-21-2010, 09:11 AM

Tear the roof off, Tear the roof off the sucker.
You've got a real type of thing going down, gettin' down. There's a whole lot of rhythm going round.

Seriously, if the sheathing looks OK from underneath, going over the old roof should save a good bit of money, and is basically impossible to see the difference from the ground.

Mike N · #10 08-21-2010, 09:14 AM

Tear it off.

**lowendfriend** · #11 08-21-2010, 09:31 AM

Remove the old or you will have spent all that money with a chance for repeat problems down the road.

sloasdaylight · #12 08-21-2010, 09:33 AM

Yea, yank that thing off. 20 years of minor leaks means you have problems with it in some form or fashion that could be costing you $$ in heating/cooling bills, not to mention, and this is more important/likely, posing a health risk because of mold/mildew build up in the wood and insulation.

Full disclosure, I have been a roofer for about 20 minutes in my entire life.

Pilgrim · #13 08-21-2010, 10:20 AM

The best way is to remove the old roofing and get a clean install. I believe that most places will allow ONE additional install of asphalt roofing over an existing roof, but that is NOT doing it right.

When it comes to a roof, do it right - don't do it half-assed.

And BTW - since you're in the Pacific NW, you lucky guy - GO, COUGS!