Sagging Floors in Homes
Sagging floors in older homes are often dismissed as simply age and tired joists and beams. However, sagging floors are often our first indicators of foundation or structural problems in old and newer homes. Several these conditions may be very significant (costly) requiring a specialists review while others actually may simply be the joists and beams are sagged from 100-150 years of stress.
Origin of common foundation and structural issues. (For brevity, I am limiting this discussion to the basement and first floor framing structure)
1) Age: leads to deterioration of components
a. rotted lumber Requires repair
b. Sagging of joists and beams (Generally not a concern unless severe) Allowable sag is Length divided by 240 (No finished ceiling below) or length divided by 360 (with finished ceiling below. In Both cases the maximum acceptable sag is ½”. (Ex. 12 foot joist divided by 240 = 0.05” less than 1/16”
c. crumbling concrete block and mortar Requires repair
2) Poor construction design and technics.
a. Undersized or over spacing joists & beams - Depending on severity May Require review by specialist
b. Undersized footings, poor soil compaction - Depending on severity May Require review by specialist
3) Home owner modifications.
a. Joists and beams cut or notched to make room for modern plumbing and heating components. Requires repair
b. columns removed below beams to “open up” the room, Requires repair
c. Increasing load on beams by opening up walls on the main floor transferring loads to new columns
Some examples of underlying causes unlevel floors
1) Rotted rim joist at the top of the foundation wall
2) Crumbling foundation wall
3) Sinking footings due to poor soil
4) Settling due to saturated soils from
a. Improper grading
b. Lack of gutters
c. Lack of proper downspout extensions
Structural issues are much more common than most people realize. Out of level, out of plumb and out of square is always the result of a structural issue. It is rare that a house is built with these conditions. Although some of these are minor concerns, they can be symptoms of serious, costly issues. Do you buyer, (and yourself) a favor and ask sellers about these items. This may reveal a known concern by the seller who “forgot” to mention it in the disclosures. This could save everyone time and your buyer an inspection fee.