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Heat control for observing deck

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#1 MattT

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Posted 27 February 2013 - 05:50 PM

Hi, I hope this is the right forum for this topic! My wife and I are in the process of buying a townhome in sunny California. I'm not planning to build an enclosed observatory (yet) but hope I could get some advice on choosing materials to minimize heat and seeing related issues at my planned scope-setup spot.

The backyard at this place has a southwest exposure with little shade and a nice view of the ecliptic, but I expect will be hot especially in the Summer. The townhomes in this community are stucco finished with comp roofs. The ~30'x30' backyard is divided approximately in half into a concrete patio half aganst the house, and a garden half against the back fence.

I plan to fill the back half of the small yard with an ornamental native plant garden, with a mulch ground covering. I'll leave an open area to set up my scope out in the garden, rather than on the patio up against the house. I don't want to have grass but am thinking of covering the observing area with the same mulch used throughout the garden. I'd guess the micro-shade provided by mulch would be better in terms of heat than a surface of compressed gravel or decomposed granite. I'd use the shredded redwood mulch sometimes called "gorilla hair," that mats down after some watering and takes light foot traffic pretty well. I might place 3 pavers or concrete pier blocks to support my tripod solidly while adding a minimum of heat-retaining mass. A subsurface harder than garden soil might be a good idea under the scope area, for setting up a day or two after rain. Any suggestions for what to use under the scope setup area, or general comments on this plan?

The concrete patio adjacent to the townhouse is in fine structural shape but needs refinishing...the previous owner painted it and the paint is wearing. I want to address the cosmetic issue in a way that minimizes heat retention, too. I think the Kool Deck concrete topper I've heard recommended for heat control is only for application to fresh concrete. Are there other coatings that are recommended for old concrete? I don't want anything really reflective, as the Sun would reflect off the patio up into my windows.

Would laying a wood, plastic, or composite deck over the patio help a lot in reducing the heat? If I go this route, what would you all suggest for decking material?

I'm thinking about rigging up an awning, perhaps made out of Solar Screen material, to shade the stucco house wall nearest the scope setup area. I'm sure I'll have to do something to shade the several windows in that wall anyway, so I'm thinking why not shade the whole wall? I can probably make an all-wall awning for the same or less cost than I'd be charged for custom framed window screens made with Solar Screen. But not sure the Homeowners' Association will go for it. The wall faces Southwest, gets no shade at all, and would be about 12-15 feet behind (Northeast of) the scope....do you think there'd be enough of a benefit from shading it to be worth the trouble?

Thanks for any advice on this project and clear skies!

#2 1965healy

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Posted 27 February 2013 - 08:15 PM

Ah condo bondage, been there, have a t-shirt. Some suggestions...
1. Get to know your neighbors, especially the ones who adjoin your backyard. Do this before you add/build anything in your yard, make allies/not enemies.
2. Read the CC&R's carefully before you attach anything to the building. Don't assume because someone else seems to have circumvented them that you can too.
3. Join the homeowners association and attend meetings. Be a part of the process, not a bystander.
4. Set up your scope in the common area during the full moon and let your neighbors look thru it. They'll think your hobby is cool rather than thinking you're looking thru their windows. If they have kids it's even cooler!

#3 MattT

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Posted 28 February 2013 - 12:43 AM

Thanks for those tips.

I just came across a product that I hadn't known existed: hardwood decking tiles.
http://www.hardwoodh.../Teaktiles.html

I thought they might make a good covering for the old concrete patio. If allowed to weather they turn silver gray and should reflect a lot of heat. But I don't see much airflow between the tile and the concrete...I wonder how much improvement they'd offer compared to a traditional deck built on top of the patio?

#4 1965healy

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Posted 28 February 2013 - 01:40 AM

Accumulated heat dissipates by either convection or conduction. You have to find a way to move cooler air over it or put something cooler on it to absorb/transfer the heat. There's a fair amount of thermal mass in a patio but it's a fairly light surface if unpainted and will probably reflect as much heat as it absorbs. Get the paint off of it and see what kind of condition the surface is in before you do much to it. A few inexpensive thermometers will give you a lot of information, put one on the concrete, one on the wall and one where you plan to observe. Monitor the readings at different times of the day/night for awhile and see what kind of
numbers you get.

#5 MattT

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Posted 02 March 2013 - 12:54 AM

Here's an interesting product for treating old concrete. This might be interesting not just for patios, but for observatories that have concrete walls, or even concrete walkways nearby. Has anyone heard about or experimented with it?
http://www.getnewloo...lStain-PRO.html

I'm sure I'll be doing a lot of experimenting myself once we're in the new place!






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