Geodesic Dome - Folding Asphalt Shingles

We have a geodesic dome roof and are about to have a new roof put on with very thick asphalt shingle-Certainteed Landmark TL. The project mgr said they will be folding the shingle under at each crease (angle at each triangle). My husband is very concerned they will eventually crack at the fold, cause curling at the one on top and the bump will be noticeable - any advice? Currently we have Masonsite shakes and they just overlap a little as they aren’t bendable. Thanks.

The TL is a great shingle, they Are no longer available in my area, but when they were we installed a lot of them and they hold up well. That being said they are not the most flexible shingle shingle on the market due to their construction.

Before installing them I would contact the local certainteed rep and make sure they will warranty the installation.

Traditional asphalt shingles are designed to lay flat. Depending on the direction and the degree of the bend we sometimes install transition metal. With lots of bends you might want to look into a SBS shingle. Best thing to do on a non typical roof would be to discuss your concerns with the rep before picking a shingle.

Those shingles are too thick to bend over anything, even just a little.

The way the do the seams would be to miter them together with aluminum flashing hidden underneath, like a mitered cedar shingle hip.

You picked the most difficult shingle to work with even on a regular roof.

1 Like

Thanks - the roofing company seems very good and they have dome experience which was hard to find. This is what they said “There is no reason for this shingles to curl , crease or crack. We are installing steel Valley metal to avoid the steep under fold from the field shingles to the dormers. That would be the only area that I may have some concerned about and we are not installing the shingles in a manner that they need to be folded. For the under folds of lower triangles going under(see picture below), we can grid out the starting point so that we don’t have the double lam exposed portion of the shingle folding under and use a flashing at the transition if you would like. IF we plan the layout so that we don’t have double lam go under the upper shingles I think we will be ok. Tim can show you these options if you would like by taking out a small piece of flashing ands opening a few shingles to show you the difference.”

They assured us the warranty would be intact. Needless to say we have a huge roof and this very expense investment needs to last.

Thanks again.

I think some of it may depend on where you live. If you live where you see longer periods of sub freezing weather in the winter and 90 degrees plus in the summer, I would not install that shingle under the conditions you describe. I’ve read about some newer products out there that are more flexible. While I’m not a GAF fan, I think they have one. I think Malarkey has one. If your Contractor is so confident about the long term viability of the Certainteed product, then have them write out their own guarantee and warranty for 30 years. If they will do that, I guess you should trust them. If not, that says it all doesn’t it?

I have done domes before – regular 30 year fiberglass/asphalt shingles will bend over the panel edges no problem, and should not crack or curl. The installer may need to hand-seal some areas depending on the shape of the dome and weather conditions during install – this is standard procedure for extremely steep areas in any case.

However I would not recommend the Landmark TL for this application – the flexibility is less, and it will be harder to get the folds to “sit down”, even with hand-sealing. So although they won’t crack, you may have trouble with corners lifting up, which will be an appearance issue and possible blow-off risk.

I’d suggest the regular Landmark or similar in this application – if you want to spend more $, as MPA and A_D suggest, Malarkey has a shingle with increased SBS content that would be excellent for this job, but the regular 30y laminates are fine in this application.

If the roof has non-dome sections, you should stick with Certainteed – then you should be able to colour-match a thinner shingle on the dome, and go with the TL on the rest of the roof.

Thanks! Well unfortunately we are too late in the process to change. Hopefully you can see the .jpg file I attached. The shingles themselves wont be laid over a seam as we doing the way it was done in the photo but the highlight area is where we need something special done. And yes we have 5 A-frames sections. We live in an area with high winds in CO. Personally I didn’t want the Landmark LT mainly because of color choices - too busy and our house is already too busy. But I much appreciate your reply.

Can’t see the entire house but that appears to be a nice look. You probably already have ice & water barrier under that entire area shown. A good crew should be able to handle that adequately.

Yeah, if they install the TL pretty much how the shakes were done it should be OK with good underlay – may need hand-sealing on the lower 3 sections and on the underlap shingles at the tops of all of them, as the lower edges may not self-adhere well enough not to stick up. Also for the middle joint where two upper sections meet there will have to be either flashing underneath (and butted as shown, like @Axiom described) or else treated as a hip with cap shingles overtop.

With the lighter shingles on a dome of this size you can roof it straight across, as though it were completely spherical – the angular joints of the dome somewhat disappear, and it looks more like a big globe than an angular polygon. Still needs quite a bit of attention to detail by the installer for it to look good though.

Yes, Ice and water shield all over and they are using adhesive on all shingled. Fingers crossed. The new shingle will not match house so we need to restain it. The ice and water is looking good, wish we would choose black shingles now. oh well. Thanks agian.

That is not what I had in mind for a geo dome, a pitch transition flashing with a clip would work on the upper part.

I meant the shallow hip formed dead centre in the two middle panels. I’ve actually done these as sort of a weave before which worked out OK, but I think it would be too bulky with TLs.

Could cap over with metal or asphalt, but the current look is probably most aesthetic.

Would look awesome with standing seam copper on it.

1 Like

This is really turning into a nightmare. They told us on the very top they would put an extra layer of something over the Ice and water shield (Tamko) on the flattest part of the dome. Now today the project coord say no shingles are on going on the top and they are using a rolled roofing product that matches the shingles. There is no way in hell they are doing that. You can see the top from the street. They are acting like they need brainstorm if that will work- omg rolled roofing is just not an option - am I missing something?

Unfortunately sometimes houses as complicated as yours are in evolving animal. What is the pitch on the uppermost portion of your house? If shakes lasted I’m sure they can get shingles to last, or is that why you are replacing the roof?

1 Like

The Masonite Woodruf’s have last 34 years with no leaks. Up top there one blew off last winter. We did have some areas where rows were failing but that the manufacture defeat and mostly on one of the A-frames-the others lasted very well. If we get 35 years out of this roof we will be very happy - but likely dead!

Flat or standing seam copper on top and do matching valleys.

Ask them what’s the pitch of the flattest section. I don’t like using shingles on anything below 3/12 (esp thicker shingles like you have) but I would have told you that before I ever took on the job. The thicker and more textured the shingle usually have a downside which is they don’t shed water as well as the old school 3 tab shingles. They do make some nice looking “rolled roofing products” some of which are designed to look like shingles.

Rolled type roofing on that architectural detail would be a travesty.

In addition to copper it could also be done with cedar shingles.

Axiom,

Would you put cedar shingles on a low slope that wouldn’t allow for comp?