# Interior insulation of an old brick house



## 29er (Mar 9, 2009)

My house was built in 1919 and I was surprised to find that it is constructed with brick walls, rather than 2x4 or 2x6 studs. The exterior has a brick veneer and the inside walls are made up of red clay tile like bricks that are 4" thick. The walls are essentially uninsulated ..... not good in Minnesota.

I would like to insulate the walls by using construction adhesive to attach 2" polystyrene directly to the interior brick wall, and then use construction adhesive to attach the sheet rock to the polystyrene. The wall is above grade and moisture is not an issue. This would allow me to avoid drilling/screwing into the brick - when I replaced windows, the brick crumbled when I tried to use Tapcon screws. The thermal bridge that 2x2 stud wall would create is also avoided. 

Questions: 
1. Is construction adhesive adequate to hold up the polystyrene and sheet rock? 

2. Are there better or easier ways to do this project? 

I appreciate any thoughts and recommendations you have


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## Tom Struble (Dec 29, 2008)

interesting .. my first thought is you should have a 1'' airspace between the brick and the foam

but i may be way off base here


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## concretemasonry (Oct 10, 2006)

Are you sure the wall is a real brick veneer or is it a thicker bonded structural wall of clay tile and brick? Are you sure the clay tile "bricks" are only 4" thick?

Are your current heating costs out of line, assuming you have done whatever is necessary for the roof and window caulking?

I had a magnificent masonry home (built in 1917) in St. Paul, Minnesota that was 10" clay tile/block with stucco and they were common in the more prosperous areas (especially with European immigrants, since wood was sign of inferior construction) because of the permanence and reasonable energy cost and superior comfort. My home had a newer gas fired circulating boiler that ran once or twice a day because of the thermal inertial of the walls and the cast iron radiators. - It was sized by HVAC contractor that did not understand the benefits of thermal mass.

If you use the correct adhesives there should be no problem. If you are paranoid and influenced by the pink panther, who is afraid of moisture and real insulation properties, there are ways to sooth that mania. The air gaps to separate a proven exterior wall from the interior are necessary because the thermal and moisture conditions are different that you consider for shoddy lightweight construction.

Dick


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## 29er (Mar 9, 2009)

Concretemasonry, it sounds like you have an interesting house with character. We looked at a lot of houses and settled on an old house because the woodwork and feel. 

A 1-2" gap exists between the exterior brick veneer and the inside clay tile/block. The dimensions of the inside bricks are 12x12 and 4" thick.

I have lived in this house 2 winters and have used a wood burning fireplace insert that supplies a significant amount of the heat. I do not really have a good way to gauge my fuel consumption. 

I checked with Liquid Nails and their low voc heavy duty construction adhesive can be used with polystyrene, brick and drywall.


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