Transcript Document
ger’s technical tune-up january 2008 part 2 Very common 1960’s solid masonry building. Typical header course. Given the age of the bldg, we would assume the backing structure is concrete block. But, where are the header courses? Should be every 16 inches. Perhaps a fake header wall? No, this is a cavity wall, so it should have weep holes and thru-wall flashing. The subject building does NOT. A fake header wall is not common, certainly not in 1960. See next slides for a modern example. Here’s an example: Old building on Church New addition has fake header course, but also has weepers and vents for PERS. See next slide. Hard to tell from phone-pic, But there are fake headers in this new wall Vents for pressure equalized rain screen weepers Maybe it’s a solid masonry brick and block wall with mortar-filled cavity and brick ties, i.e. no weep holes. These are fairly common, BUT, they DON’T have header courses, fake or not. There would be no point. Eg. Circa 1975 . Brick with no header courses... …But no flashing or weep holes, either. Here’s the inside. Block, no headers. Load bearing wall, by the way - supports steel roof structure. Per exterior picture, this isn’t it. Another possibility • Could be a wall with 3 wythes of 4-inch units, with outer brick headered to middle (4-inch block) only. • If this is the case, the middle wythe must be tied to the interior wythe of 4-inch block with metal ties. • This is possible….but I doubt that 3-wythe walls are common for 40-50 year old industrial buildings. Seems unnecessarily complicated to build. So…what is it? Per Architectural Graphics Standards (Al’s copy, circa 1950), we likely are looking at a Header Block wall, 12” deep. COOL! What Did We Learn? • Technical – Solid masonry walls come in a variety of styles, as do concrete blocks – “Header blocks” have an extra ledge that conventional blocks don’t – no big deal • Psychological – Given how common this building age & style is, have we “seen” this before but not noticed it? – Micro inspection (for defects) can easily overshadow Macro inspection (big picture) – don’t forget to see the forest for the trees – Don’t inspect on Autopilot!! What Else Did We Learn? • Tautological – I haven’t observed the actual wall construction of one of these yet, so this is an educated guess. – But, I can tell you that I’ve seen these walls a few times now since I first noticed it. – If anyone has any further thoughts or observations, let me know! • Astronomical! – Al’s text book is from 1950?! – We can conclude that when Al was born, people could be seen jumping up and down. Not for joy, but because the earth’s crust was still pretty hot back then.