Keep the lattice. It's a beautiful, historically accurate touch and the ventilation it provides is important in allowing the porch flooring and other components to dry out. Putting some sort of rigid type insulation such as styrofoam against the foundation walls may help, but I would think this would probably not be cost or effort effective.

You have a beautiful house which appears to be in superb condition.Be cautious about adding insulation anywhere. Buildings like this one have lasted in such good shape for more than 100 years because they are able to "breathe". Adding insulation can cause a great many problems with moisture and rot. At the very least, see if you can consult with someone with expertise in historic homes before adding insulation. No matter how well intentioned they may be, insulation contractors are rarely experts on old houses.

I agree with mainegrower. Please don't insulate. Your home has done just fine without it for over 100 years. Why ruin a good thing now. What prompted the recommendations in the first place?

I especially agree with the comments about insulation and HVAC contractors who aren't super intimately familiar with old homes. Do not rely on them for anything!

How would insulating under an outdoor porch help anything? Is there a foundation? If so, that's the only thing worth considering insulating, and probably better to do it on the inside. If there are piers under the entire house (i.e., no basement) then you could insulate under/between the floor joists.

I can't answer your question but wanted to comment. Your house is so beautiful! Makes mine look so very boring lol.

Our plan is to keep the lattice no matter whether we "close" it in or not. If we close in, we will simply put up a piece of solid board behind the lattice. The lattice goes all the way around the house which means the house is completely up off the ground and there is approximately 5 feet of space between the ground and the floor joists under the entire house. For the most part, we do not have basements in this part of Texas. We were not planning on insulating under the house due to humidity and rodents. We were thinking that just closing it in would help with any Northern winds in the winter that would chill the house from underneath, but I began to worry that would hinder the houses' requirements for ventilation or that it would encourage mold/mildew. And thanks so much for the compliment. We don't live in it yet...3 months and counting.

If the winter winds are a serious problem, what about insulating panels that could be put up on the exterior of the lattice in the winter and removed in the spring? Insulating between the floor joists would also do more for warmth than a barrier behind the lattice. A barrier there would also impede venitilation. Ventilation is even more important with no foundation than with one. I'd once again suggest consulting an old house expert. There are types of rodent/insect resistant insulation that might work very well sprayed between the floor joists.

Our house and porch are insulated between the floor joists as stated above. It works great. I also stress that you will create some big moisture problems if you enclose the lattice portion. Besides it is so pretty!
Diane

I'm not really understanding why the insulation will create humidity problems. Or rodent problems. I would put insulation in between the floor joists wherever it is below interior areas. I would then cover that insulation with a vapor barrier (tyvek). I would then nail up some plywood over the insulation, pressure treated if that's really damp, but at 5 feet off ground, not necessary. That will "seal in" the insulation, preventing any rodents from nesting in (as will five feet of height). If it's an old house, moisture will have plenty of ways to escape or get in, through walls, doors, windows, and so on. Underneath the house should be pretty dry anyway, since it won't get rain directly (our covered porch, which is on piers) has bone-dry dirt, even though everything around it is damp.

I don't know about its availability in the US, but when I lived in Australia, where this type of construction (no basement, elevated, ventilated underneath) is pretty much the norm. Ventilation is important as is the ability of the floor to breathe.

What they use in Oz is a foil insulation product that is perforated. It will insulate, reduce/eliminate draughts but still breathe.

The idea of fibreglass insulation and tyvek paper is an interesting one, I suppose kraft paper backed would work too? I assume it's considered breathable. Only issue is, rodents/vermin like fibreglass.

I have to echo the others' comments, your house is beautiful.

thanks to everyone for their input/suggestions & compliments. much appreciated.

Be careful where you add a vapor retarder. An asphalt-coated kraft-paper facing on fiberglass insulation is a vapor retarder but Tyvek HomeWrap is not. (Ironically spun-bonded polyolefin was invented for use on the bottom of furniture)

I don't understand what possible purpose there would be to enclose the bottom of an open porch. It is essential to keep this area open for ventilation if you want to avoid having to replace the porch. If the whole house is open underneath the insulated barrier should be added at the exterior wall line.

These are additional pics of my house from different sides. Perhaps it was confusing showing the front of the house with the porch, as the lattice panels are on all sides of the house. What we think we will do is simply leave the lattice panels, install a sheet of dark painted plywood behind the lattice so it will all but disappear from the front and the lattice will be all you really see. We think we will do this only on the North & South end of the house but leave the East/West sides lattice panels open for ventilation. I do not live in the house yet...but when we are there during the cold months working on it...it is colder inside than it is outside. The house is completely off the ground on average 5 feet. thanks again

FYI, stopping the ventilation will have detrimental effects on your wood porch. Poor ventilation is usually what rots a wood porch out, not rain or other obvious sources of water.