Help from the Alps!!!

[nalmeida]

Well, I'm just curious to be honest, I recently bought this kit to integrate in my n layout:

Vollmer - 7742 - Restaurant

I include a picture below, my question is, why do you put the rocks in the roof? I first tought it might be because of the snow but this would only put more weight on it, so could anyone clear thin one out?

EDIT: This is the image from the box, I will make some changes in my kit.

 

[billk]

I can't tell from picture if the building has a slate roof, but sometimes rocks are put on that type of roof to keep the slates from blowing off. (Ain't Google great?)

 

[MasonJar]

Bill has the answer...

You would think that a stone roof would be heavy enough to hold itself down, but the slate is actually quite thin, and can be lifted by strong gusts. Some slate and other stone roofing is simply hung on boards running across the roof - not even nailed or tied down! So the extra rocks help keep everything in place.

Andrew

 

[Sir_Prize]

Could it be a heat thing?
The rocks warm up quicker when hit with sunlight, which in turn
melts the snow. They also, hold down the tiles.

 

[Fred_M]

I thought it was to keep the snow and ice from sliding off the roof in the winter in a big sheet and injuring people. Like ice dams. ??? FRED

 

[billk]

Here's a quote from http://www.tourvelo.org/swisalps.html

as the trail wound up past ancient timbered farms with rocks on the roof to keep the slates from blowing off

Of course, anything on the internet should be taken with several grains of salt (including this posting).

 

[cidchase]

In Texas and Oklahoma they throw old tires up on top of
the mobile homes to keep the roofing on in the breeze.

Course, that's in "Tornado Alley"

 

[Fred_M]

Originally posted by cidchase
In Texas and Oklahoma they throw old tires up on top of
the mobile homes to keep the roofing on in the breeze.

Course, that's in "Tornado Alley"

Not just there, everywhere you find a house trailer, you find tires on the roof. It's just part of the trailer . FRED

 

[cidchase]

I'm sure you're right Fred, I just noticed it a lot more driving
out there. I was told it was because of the wind, made sense
to me, it never stops blowin' in West Texas!

Tumbleweeds and sand-blasted windshields! I suppose that
locomotives constantly en route thru there need their
windshields replaced more often (just to get this back on
trains, sorry fer the diversion)

 

[RailRon]

I know these rocks quite well, since I used to spend my summer holidays in a mountain farmer family in the Alps when I was a kid. We had shingle roofs, not slates.

As far as I see from the pics, that's also a shingle roof. The stones not only prevent single slates from flying away, they are holding back the whole roof in a storm.

If you look at the roof of such a hut and imagine the wind flowing over it, you have the same airflow like on the wing of an airplane: The wind near the roof has to cover a longer distance than the wind higher up in the air. The result is a suction over the roof and therefore an ascending force (red arrow), which tries to lift the roof off.

And believe me, we have winds up there which simply tear a roof off, when it isn't weighted down enough. One summer, a neighbour built a new stable and finally they shingled the roof. When they had finished, a thunderstorm came along. They hadn't had the time to lift the heavy rocks onto the roof, although they were ready, lying beside the road. This evening the wind tore off the brand new roof, while we were watching, completely horrified. I'll never forgot the sight of the whole roof taking of, sailing away and disintegrating in its flight! (Luckily no one and nothing was hit by the debris.)

So Nelson, better put these rocks on your mountain restaurant, before the roof flies away when somebody sneezes near your layout!

Ron

 

[nalmeida]

Thanks for the fantastic explanation Ron (and to everyone), this solves my problem because I wasn't sure if I would put them or not. Since the restaurant is in the bottom of a mountain I'll leave the rocks out, aestheticaly (probably mispelled) i prefer it this way.