[jrref]

Originally Posted by rsmurano

If you enclose your lanai, you definitely want to insulate your attic. If the lanai is just screened in, don’t waste your money on insulation, what good will insulation give you in the attic when your open space is 140 degrees because of all the cement, floor and house block wall.

Actually, even if you don't enclose your lanai, insulating the lanai attic will prevent the ceiling from cracking. Same for the garage. If you don't insulate you will get cracks forever.

[retiredguy123]

Originally Posted by jrref

Actually, even if you don't enclose your lanai, insulating the lanai attic will prevent the ceiling from cracking. Same for the garage. If you don't insulate you will get cracks forever.

Do you have any objective evidence to support this? My 10 year old lanai and garage ceilings have no insulation and no cracks.

[jrref]

Originally Posted by retiredguy123

Do you have any objective evidence to support this? My 10 year old lanai and garage ceilings have no insulation and no cracks.

Your home seems to be the exception. Almost every home I've been in has minor cracking in the garage and lanai ceiling. Most of the time it's because the ceiling super heats in the summer months. Lori who owns "A Touch of Drywall", who specializes in drywall repair here in the Villages will not repair your garage or Lani ceiling unless you have insulation because of the heatng problems causing cracks. Now, it's possible some homes may be oriented so the garage and lanai are not in the hot sun during the hottest parts of the day which may be the reason why some don't crack.

[retiredguy123]

Originally Posted by jrref

Your home seems to be the exception. Almost every home I've been in has minor cracking in the garage and lanai ceiling. Most of the time it's because the ceiling super heats in the summer months. Lori who owns "A Touch of Drywall", who specializes in drywall repair here in the Villages will not repair your garage or Lani ceiling unless you have insulation because of the heatng problems causing cracks. Now, it's possible some homes may be oriented so the garage and lanai are not in the hot sun during the hottest parts of the day which may be the reason why some don't crack.

I don't know what you mean by "super heat", but, from a scientific heat transfer basis, the ceiling in an unconditioned space will be the same temperature whether it is insulated or not. If the attic heats up very quickly, the insulation may slow down the transfer of heat, but within an hour or so, the temperature above and below the drywall ceiling will reach an equilibrium status and they will become the same temperature. This assumes that you measure the actual temperature of the drywall. So, I don't think the insulation will have much effect, if any, on the tendency for the drywall to crack. The building industry has a long standing policy that you insulate between conditioned and unconditioned spaces, but that you do not insulate between two unconditioned spaces.

[elevatorman]

We have a Begonia model. When we moved in we wanted to enclose the lanai eventually so we had our lanai insulated. Since the ceiling is higher in the living room than the lanai there is a 2 foot wall above the sliding glass door that is exposed to the attic .During the insulating process we found out that wall had never been insulated. When the insulation was initially installed it was blown into the attic space over the living space. That wall was in the back and not seen when insulating. If this is the same in your home I would recommend insulating the lanai.
The builders were still working in my neighborhood at the time so i looked for an insulating company name on the truck and asked the guys if they could do my lanai. They gave me a price and I gave them cash.
By the way there should be a sticker on your air handler that has the R value installed in your home. It will have the company name of the insulating company.

[jrref]

Originally Posted by retiredguy123

I don't know what you mean by "super heat", but, from a scientific heat transfer basis, the ceiling in an unconditioned space will be the same temperature whether it is insulated or not. If the attic heats up very quickly, the insulation may slow down the transfer of heat, but within an hour or so, the temperature above and below the drywall ceiling will reach an equilibrium status and they will become the same temperature. This assumes that you measure the actual temperature of the drywall. So, I don't think the insulation will have much effect, if any, on the tendency for the drywall to crack. The building industry has a long standing policy that you insulate between conditioned and unconditioned spaces, but that you do not insulate between two unconditioned spaces.

So, eventhough the open lanai is at outside air temperature, the sun beating on your roof will heat up the air in the attic. It can go up to 150 degrees on a very hot day. The insulation will prevent the sheetrock from reaching that temperature. I know this because I put a wireless thermometer in the attic over the lanai and also measured the ceiling temperature before and after the insulation was put in the lanai ceiling. Same goes for the garage ceiling.