DIY spray foam your own walls and / or attic. It can be done from the inside or outside. I will try to make this long story short but it won't be easy. 2012 we moved into a1970's built house. It was drafty. If I took a cover off an electrical outlet, the breeze could have put out a lighted match and around windows and baseboard I could feel air flow. Winter 2013 very old so I started exploring spray foam. I called a local company to do the attic ceilings in January. They were going to come out on a freezing windy day in January. I told them it was too cold to have the door open with their long hoses coming in. Since I put it off, that gave me time to do more research on spray foam. I learned that too cold of a temperature might not get a good attachment to the surface. The local company should have known that but wanted the money would have done it anyway. I paid them later to do two attic ceilings with open cell. They took no care in protecting overspray getting on ceiling vents or anything else. I thought I could do a better job myself and found this Foam it green DIY website. Although extremely nervous the first time, I sprayed the attic floor and walls after getting help removing filthy blown in loose insulation off the attic floors using closed cell spray foam. A nephew helped me scoop up the old loose stuff wearing hospital gloves and masks. We scooped it out using dustpans and brooms mostly. After a couple of more years, we redid a portion of exterior siding which gave me opportunity to spray from the outside in that area. I had one wall of sheetrock removed on one portion inside the house that had large windows with drafts. I used closed cell on the horizontal walls for added density and strength. The open cell used by the local company on the attic ceiling shrunk over time and my closed cell in the attic floor did not. The kits of this DIY green foam is better than some other brands sold at home center stores. The foam it green DIY site Lots of instructional videos on their website. They offer open cell, closed cell, and ultra dense closed cell. read more