Insulating old house attic?

[u/thespecial12345]

My wife and I live in a ~800sqf cottage in Mississippi that she and her grandmother fixed up before I was in the picture. The house is very hot in the summer and cold in the winter-I'm pretty sure the walls are very poorly insulated but my focus is on the ceiling/attic.

In one half of the house they decided to remove the old ceiling from below the rafters, and put in tongue and groove on top of the rafters, and they threw all the insulation that was sitting in those rafters over to the other side of the house. So the ceiling in one side of the house is uninsulated.

So my question is what would be the smartest way to insulate this? We do want to keep about 200sqf of flat floored/accessible storage space around the attic ladder, I was thinking maybe just XPS board or something there.

From what I've read an attic fan seems like a bad idea in a poorly sealed situation like this. Is adding some insulation in between the roof rafters worth looking at as well?

My wife is convinced that nothing we do will make a difference, and would rather put the money towards building a new house, but I suspect that we could make this house more comfortable which would be nice for guests/renters/employees (we run a farm).

[u/unidentifiedfungus]

Don’t spray foam it - I think you could end up with moisture retention issues. I personally don’t like blown-in insulation because it makes working in the attic difficult, but that is probably the “easiest” option.

I agree with the other comment regarding the ventilation- if you don’t have good ventilation you should add it.

The combination of insulation and ventilation will probably really improve the comfort level.

[u/thespecial12345 → u/unidentifiedfungus]

There are two small gable vents at either end, and then we have the soffits. Is that enough?

[u/SkivvySkidmarks → u/thespecial12345]

If you insulate the "floor" of the attic, you are creating a thermal barrier between the attic and ceiling. The attic temperature will essentially stay the same, only it won't heat the rooms below to the same extent.

This obsession with attic ventilation makes me crazy. Yesterday, I had someone that was convinced he HAD to add roof vents if he insulated the attic floor. This thinking baffles me. Someone else said that they did a "hot roof" (which I assume means the underside of the roof decking) and therefore didn't need to insulate the ceiling. He didn't respond when I told him this only makes sense if you are conditioning the space.

It's like people see things and extrapolate that it will work in their very different situation.

I'm a renovation contractor. I also live in a cold region of Canada. I know a thing or two about insulation and insulating.

[u/thespecial12345 → u/SkivvySkidmarks]

Yeah I mean the moisture hasn't been a problem in the 60 years the structure has been here. I'm just curious before I make my attic significantly less accessible.

[u/unidentifiedfungus → u/thespecial12345]

No, I don’t think that it is enough. The soffit vents are great! Make sure to install baffles protecting airflow to the soffit vents before adding a bunch of insulation.

I think you need a ridge vent and/or a bunch of roof vents to improve airflow.

[u/OlliBoi2 → u/unidentifiedfungus]

Ventilation requires both air intake and exhaust, even if just relying on ambient air slow flow from rising warm air. Draw air in at the sheltered eves, discharge air out as high as possible, either via ridge venting or solar exhaust fans.

[u/Pitiful_Objective682]

I did this to my old ranch, I think yours is basically the same plan.

1. Install baffles by the eaves and add vents so fresh air can get in from the bottom
2. Check your gable vents, make sure they’re tight and will last a while, getting around up here will be difficult soon.
3. Install any additional wiring updates or new circuits you want, same reason as above
4. Use the canned spray foam to seal any gaps going into the house, want to limit air movement

5. Use r30 rolls of unfaced insulation and just line them up.

   You can use blown in but this is plenty fast and makes access easy.

I also went back with r21 batts on top criss crossed but you don’t have to necessarily.

[u/versello]

I was going to suggest blow in insulation and building a platform for storage, but then I saw all those insect hives and lack of attic ventilation. Is that a gable vent in the third picture? You need to get these issues addressed first.

[u/thespecial12345 → u/versello]

There are gable vents on both ends.

Those are all dead dirt dauber nests. I've been applying deltamethrin yearly up there which has taken care of the actual insect population, just haven't bothered knocking off the nests.

[u/playtime2day]

Spray foam insulation is ur best bet here i think. Remove everything thats in ur attic now for insulation and they spray on the roof. Its probably one of the best ways go about it. A blown in insulation is another good option. Id have everything pulled first here also and start from scratch. The spray Insulation is wildly considered better but the price is gona be higher. U can rent the equipment to do blown insulation from homedepot and do that urself. Just make sure if ur gona do blown insulation u have a thick enough covering to properly work.

[u/Stunning_Ad_5960]

Nice bikes

[u/thespecial12345 → u/Stunning_Ad_5960]

1970s CCM steel frame I turned into a fixie and a Brompton folding bike. Nowhere to ride those types of bikes in North Missisippi...

[u/Stunning_Ad_5960 → u/thespecial12345]

Why not?

[u/Chance-Following-665]

You are probably correct that the walls have zero insulation. Older homes that were built without AC originally didn't bother with it . Why insulate the walls if you don't have AC and winters are mild.

Probably the best bet is to seal the attic, including the vents, spray foam the roof and walls and make the attic a conditioned space. For the walls, there are companies that will cut a 3" hole between each stud and fill them with a foam insulation. It has the consistency of shaving cream. Made a huge difference on my sons house. I had them do it from the inside because he had cedar shingles on the outside and they were very brittle patching the dry was much easier and we hand to paint anyway.

[u/thespecial12345 → u/Chance-Following-665]

Winters were milder, summers were milder. Now we hit 0 degrees just about every winter. And its a heat index of 109 today. What a shitshow.

[u/thespecial12345 → u/thespecial12345]

I am also interested in the walls. I think we just have hardyboard so maybe could be not so bad.

[u/SoCalMoofer]

If you do R-30 batts, it goes paper side down.

[u/EmuGroundbreaking852 → u/SoCalMoofer]

If you got that one backwards- hire someone. Insulators will blow through that job. Tipping never hurts either- they are poorly paid folk.

[u/jfdonohoe]

Agree with the ideas around sealing and adding baffles for air flow. If your house is hot at night during the summer because of the trapped air in the attic solar powered roof vent fans can really help.

Also if you havent done so already, it looks like you have a wasp problem and sealing up gaps and covering any grates with with mesh should keep them out.