Moisture Protection Building Envelopes

1. Moisture ProtectionBuilding Envelopes Christopher Perego Market Segment Manager – Building Restoration Shakopee, MN November 2, 2010

2. Moisture Protection for Building Envelopes

3. Program Objectives • Basics of wall design • The trouble with buildings • Façade repair systems • Case histories • Questions

4. Value Proposition • Consultant’s consultant • Material science • Building science • Problem solving • Adjacent materials • What does the bundle mean?

5. Beyond the Bundle

6. The Basics of Wall Design Brick Precast Stucco Masonry

7. Masonry Design Issues

8. Why Design With Masonry?

9. Masonry Design Issues Benefits • Versatility and beauty • Durability • Fire resistance • Life cycle cost effectiveness • Flexibility • Economy

10. Masonry Design Issues Challenges • Moisture and water management • Efflorescence • Cracks and spalls • Block is porous • No one to take responsibility “The coat of arms.”

11. 9 Out of 10 Architects Surveyed Say….. #1 concern with masonry.... Moisture

12. Masonry Wall Design Concepts

13. Four Keys to Masonry Wall Design Protection • Protection from moisture Collection • Collect any water that gets through the face shell Drainage • Provide a path for water to exit the wall section Backup • Have a backup plan if the first three fail

14. Wall Design Concepts Barrier Wall • Single layer of protection • Relies on perfection • No back-up • Very common wall system for Office/Warehouse

15. Wall Design Concepts Cavity Wall • Double layer of protection • Protection • Collection • Drainage • Back up • Expensive

16. The Reality All wall systems should have these Most single-wythe walls miss some key design details Moisture protection even more important on single-wythe walls Most paint peels from sealant Masonry cracks for many reasons The Solution Need to use a variety of elements to waterproof wall Most single-wythe walls leak Most single-wythe walls need repair and a breathable membrane Use coatings compatible with sealants Use a membrane that can bridge cracks Wall Design ConceptsProtection,collection,drainage,back-up

17. Protection for Single WytheBarrier Coatings

18. Wall Design ConceptsCollection • Water will get into cavity at some time via settlement cracks, details, pinholes • Need to provide an unobstructed core for water to pass down via gravity • Need flashing to capture and gather water

19. Wall Design ConceptsDrainage • Need to manage water that gets into the cavity • Need unobstructed path for water • Need weeps for water to exit the cavity • Water must drain to prevent other problems

20. Wall Design ConceptsBackup • There are no provisions for back-up in a single-wythe wall • All the moisture protection for a single-wythe building is on the surface • It is important on this type of wall to choose the right surface treatment

21. The Trouble with BuildingsSingle-wythe masonry walls – why do they leak? • Mortar laid too far ahead of mason, not enough water to carry Portland and sand into block or brick – results in crack • Clip joints – not fully loaded head joints, does not hold water • Improperly tooled joints • Blocked cavity • Weep tubes blocked • Penetrations not caulked • Leaks at head jam of window

22. The Trouble with BuildingsSingle-wythe masonry walls – why do they leak? • Settlement cracks • No flashing • Wet insulation during construction • 100 year storms • Negative vapor pressure • Improper grading • Parapet cap details • Inadequate design – specifying only minimum protection • Poor sealant details

23. The Trouble with BuildingsSingle-wythe masonry walls – why do they leak? ………and sometimes, it just seems we have angered the rain Gods!

24. Façade Repair Systems • Assessment • Surface preparation • Material compatibility issues • Repairs • Waterproofing for long term protection

25. Repair Systems - Assessment “Prescription before diagnosis is malpractice” – unknown • Most older buildings require a combination of repairs • Most older single-wythe masonry building require a barrier coating • Tuck pointing and block replacement important part of system

26. Repair System – Surface Preparation • Tuck pointing – all deteriorating mortar, cracks larger than 1/32 – inch, signs of rust bleed, efflorescence, excessive moisture • Block replacement as necessary – more than ¼ of block spalled, top edge of block deteriorated, or block with transverse cracks • Flashing – install flashing as necessary over opening and changes in elevation

27. Repair System – Surface Preparation

28. Repair System – Surface Preparation • Cleaning – remove all efflorescence, mold, mildew, rust stains • Remove all existing coating that is unsound • Repair minor spalls with compatible repair mortar, follow ICRI guidelines for repair • Repair sealant in control joints, as necessary

29. Repair System – Detailing

30. Material Compatibility • Use a soft mortar for tuck pointing • Choose patching material with similar properties to substrate • Large scale patching not recommended – block removal best option if patches get large • Avoid silicone surface treatments

31. Material Compatibility • Use elastomeric coating over elastomeric sealant • Tint sealant to similar color as wall coating • Do not mix urethane and silicone on the same project

32. Repair Issues

33. Review and Questions

34. Sources • Waterproofing the Building Envelope – Michael Kubal • Concrete Masonry Handbook – Panarese, Kosmatka • National Concrete and Masonry Association • Southern Brick Institute • American Concrete Institute • Brick Industry Association

36. Commercial Buildings

37. Residential Buildings

38. Parking Garages

39. Troubleshooting

40. Troubleshooting

41. Troubleshooting

42. Troubleshooting

43. Troubleshooting