Wood support beams cracked

Bought a house built in 1962 2 years ago. It is a ranch style house. The structural wood beams had a little bow in it and a couple small cracks, the inspector said it was fine and not to worry. Today, we noticed a bunch of additional cracks and are very nervous about them. I have attached pictures and would like suggestions on whether or not we need to replace. We have been hit like the rest of the us and lost our jobs so I don’t want any additional cost if not necessary but want my family to be safe.

Non-members are not allowed to post photo’s on the MB, but doesn’t matter too much.

Contact a local, reputable, qualified contractor for evaluation and repair. Get three or more estimates and disregard any that are significantly cheaper than the others. Also make sure you obtain any required building permits. If the contractor says he will obtain them, verify that he does. Clue: if he doesn’t post it in a conspicuous location, ie… front window, he may not have obtained one.

Any bowing with cracking is not good. I understand your financial situation, but what value do you place on your families safety? Don’t mean to sound harsh, but it is the basic truth.

BTW… where are you located? Someone here may be able to recommend a contractor in your area.

Good luck.

You’re welcome to email the pictures to me and I’ll post them as soon as I can.

Jeff has some good ponts and it is hard to say what it is without seeing it.

whis11 @ charter.net (take out the spaces)

In general wood beams should not have a noticeable bow, unless it was installed with the natural curve/crown down. And new cracking is a concern no matter how ya slice it. I agree it doesn’t sound good on the surface.

A proper evaluation from just photos can’t be done, and shouldn’t be relied upon. Maybe just call the inspector to come back and take another look, and/or get a referral for a specialist to look at it for you. It you just call a contractor your not likely to get an independent evaluation of the situation, and probably will just get a repair estimate. Good luck.

And, it could be as simple as surface checking…

Possible if the cracks were initially missed … but wouldn’t be for new cracking (per the description) as checks are the result of differential shrinkage from the lumber initially drying out.

I will through in my 2 cents. I agree with Jeffery.
Some timbers and wood used in the making of rafters( lower cord ) are known to bow when humid.
These puzzled architects and engineers. It is thought to be trees that have grown on hillsides with a steep pitch. they have a natural one sided thicker growth ring at compensates the lateral forces when growing.
I will look for the article. Been 2 years.

That sounds like whats called “truss uplift”. Its most often from different humidity/moisture conditions between the upper uninsulated top chords and the lower insulated bottom cords of roof truss framing. Due to the different moisture conditions, the bottom chord will bow upward. But it doesn’t sound like thats whats being described.

Some distortion and surface cracks (checks) are normal for wood framing members due to different shrinkage across the width and height as the lumber initially dries out. You can also get some warping along the length that looks like a slightly sagging member (called crooks) from different shrinkage lengthwise between the top and bottom of the lumber on pieces with mixed juvenile and old growth, or even mixed reaction wood (e.g. tree on a slope).

That might be what your thinking of. But thats typically not significant enough to be mistaken for visible sagging with average framing lumber, as it’s usually isolated to only certain mill cut pieces (near the centerline on one side) on mixed growth trees for larger lumber (e.g. 2x12), and wouldn’t cause new cracking.

P.S. It’s way beyond a home inspection to get into issues like these. But A good resource is the FPL Wood Handbook … free PDF download.


Thank you. Truss uplift.
Do you have any literature or links I can go to.


Its like magic.
Next time I will just think it. HA HA HA
Thanks mate.

Since you were thinking it, here’s another link on truss uplift … shazam … :wink:



Most ceiling sheetrock cracking is caused by truss movement usually traced back to Wind, Thermal, or Installation. Here are some abreviated conclusions which I have experienced first-hand during inspections;
Wind uplift due to negative pressure on roof sheathing and/or attic (balloon) pressure through vents is causing excessive truss movement which the brittle sheetrock joints cannot withstand. This is confirmed by truss calculations of the longspan truss showing an L/107 deflection of the 15’ bottom chord panel lengths.
Wind exposure on the large porch ceiling is creating an uplift on the bottom chord and the toe-nailed connections have broken loose from the wall. Replace toe-nailed connection with hurricane ties at the exterior wall similar to those that were installed on the porch beam.
Ceiling sheetrock was installed on green lumber truss bottom chords with a moisture content in excess of 19% on a hot summer day. Sheetrock panel-butt splices have now telegraphed through showing an 1/8" ridge in a 4x8 pattern on the entire garage ceiling surface. The same sheetrock installer did both the house and garage, but the garage is not insulated and therefor subjected to more extreme with the 9 degree winter temperature.
The longspan scissor trusses at the great-room entrance will deflect (breathe) during snow and temperature changes. The same sheetrocker did both houses of the same model and only yours shows sheetrock cracking at the parallel interior wall and 4’oc cracks near centerline perpendicular to trusses. Because the other owner lives there year-round, and yours is a vacation home visited infrequently, the cracks are easily explained by thermal changes. When your heat is totally off while you are away, the attic/house temperature nears an ambient 25 degrees this week. When you arrive and heat the conditioned space to 75+ degrees, the truss bottom chord warms and expands causing a truss vertical deflection. This same deflection can happen when your roof snow load goes from zero to 3’ of snow. The truss has been designed to carry the load, but deflects (breathes) when it is applied. This movement will break the sheetrock corner joint next to a stationary parallel wall.
When the truss was installed reversed, it caused an interior bearing to occur in a mid-panel instead of the designed-for truss joint. The dead load truss deflection created a crown in the bottom chord at that bearing which made an ‘S’ wave in the entire ceiling.
Cambered trusses were forced down 1/2" to interior bearings and toe-nailed to top plate in lieu of vertical slotted panel stabilizing clips. After 6 months, random sheetrock cracks occured at interior walls where the truss returned upward and pulled some toe-nails out.
Trusses were toe-nailed to interior wall top plates. The alluvial soil beneath the slab settled and so did SOME walls creating up to 1" gaps between the ceiling and top plate, or between the sole-plate and slab. The trusses were too-strong and pulled the interior walls off the slab and broke the sole-plate (red-head) slab connection.
bylar (Structural)19 Dec 05 17:13
I have found similar causes but if the sheetrock is installed as per the manufactures recommendation and the joint at the wall is not nailed but allowed to float cracking at the wall will be avoided.

Thanks guys.:slight_smile: