Pilaster vs. Buttress

Originally Posted By: Michael D Thomas
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Can someone give me a description of the difference between a pilaster and a buttress used to reinforce a foundation wall? - Thanks.


Originally Posted By: staylor
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A pilaster is a column built within a wall and projects out past the wall plane. It is designed to carry a load from above- not to strengthen the wall against lateral loads.


A buttress is typically an exterior pier of masonry, ofter sloped, and used to strengthen or support a wall or prevent movement from lateral loads.


Originally Posted By: kmcmahon
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A butress


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Originally Posted By: kmcmahon
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A pilaster






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Originally Posted By: dvalley
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PILASTER


BUTTRESS


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David Valley
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Originally Posted By: Michael D Thomas
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staylor wrote:
A pilaster is a column built within a wall and projects out past the wall plane. It is designed to carry a load from above- not to strengthen the wall against lateral loads.
A buttress is typically an exterior pier of masonry, ofter sloped, and used to strengthen or support a wall or prevent movement from lateral loads.


This is what's confusing me.

The illustrations on this site (the same two mentioned by dvaley above) show a plaister used to control lateral movement.

http://www.nachi.org/tips/0257.gif

and show little difference for a buttress

http://www.nachi.org/tips/0256.gif


Originally Posted By: dvalley
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is simply a structural support element in a building, usually constructed of concrete or masonry, built against a wall for support.


A pilaster is simply a pillar or column set into a wall as an ornamental feature. An exterior mass of masonry set at an angle to strengthen a wall or support


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Originally Posted By: roconnor
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staylor wrote:
A pilaster is a column built within a wall and projects out past the wall plane. It is designed to carry a load from above- not to strengthen the wall against lateral loads.

Michael D Thomas wrote:
This is what's confusing me. The illustrations on this site show a plaister used to control lateral movement.

Actually a pilaster can be used either like a column to support vertical load, or it can be used like a beam spanning from floor to floor to provide lateral support for a wall. However, most people think in terms of a pilaster acting like a column. A buttress is a free standing element only used to provide lateral support for a wall (similar to a bookshelf support bracket).

Note that there is an inconsistency in Tip #0257 "Foundation Repairs - Adding a Pilaster". The Tip notes that a connection to the floor will increase the strength, but the way it's used there it would have very little strength without that connection


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