Water Testing and Analysis

Now we have finished the water test of the Reverse Brick Veneer wall we have built. Dean was recording the test and Angelo was doing the test. Kangping and Feng were behind the wall.

Result:
1. In general, the wall performed well as we have expected. 
2. The structural integrity was good, the water did not do any damage to the wall structure, including the weatherboard, the timber framing, and the Hebel block wall.
3. The weatherboards were wet as expected, the Hebel block wall was absolutely dry, and the cavity between the timber framing and the Hebel block was also safe from any water.
4. HOWEVER, there was some minor leak from the bottom of the window frame.

Photo. 01 The Weatherboards and Window were wet

Photo. 02 The Hebel Blocks to the Right of the Window were dry

Photo. 03 The Hebel Blocks above the Window were Dry

Photo. 04 The Hebel Blocks to the Left of the Window were Dry

Photo. 05 Kangping was Testing if the Cavity was Protected from Water

Photo. 06 The Timber Framing, The Side of Hebel Blocks, and The Cavity in between were Dry

Photo. 07 Obvious Trace of Water Leaking to the Interior

Photo. 08 Closer Look at the Leakage, Obvious Water Trace from the Bottom of the Window Frame

Photo. 09 Group Photo after the Test

Analysis:
As the cavity between the timber framing and the Hebel block wall were both dry, the weatherboards worked as it was supposed to and protected the main structure from any water contact. And it also means the water leaked to the interior did not come from gaps between weatherboards or anything like that. Additional, there was obvious trace of water coming through the bottom of the window framing, we can then determine that the leakage was caused by inappropriate sealing of the window frame and it appears to be the only problem we had for the wall.

The problem maybe caused by not leveling the window properly or insufficient silicon was used when sealing the gap. But the solution to this is quite simple. Simply applying more silicon to seal the gap will fix the problem and prevent further leakage.

Construction Process

Picture 01-04. Measuring and cutting the Hebel blocks (with hand saw) according to proposed design.

Picture. 05 Kangping and Angelo were leveling

Picture 06. Dean was mixing the cement. According to the instruction, it was mixed with 250g cement and 1.25L water. 

Picture 07. Angelo and Dean were laying the first layer of Hebel blocks (Number 1-3). Cement were put on both sides and bottom of the blocks.

Picture 08. Angelo and Kangping were laying the second layer of the Hebel blocks (Number 3-5). 

Picture 09. Feng and Dean were laying the third layer of Hebel blocks (Number 6-8). We changed the design a little bit at the site. By switching Block 7 and Block 8, we now have the gaps between every two blocks aligned with the centre of the blocks above and under.

Picture 10. The “brick” layer of the RBV construction.

Picture 11-12. Dean was putting up timber sheet and blocks as temporary bracing to support the wall before the cement sets.

Picture 13. Angelo and Dean were cutting the redundant window frame.

Picture 14. Window after frame being trimmed.

Picture 15-18. Angelo, Feng and Dean were assembling the new plywood window frame.

Picture 19. Angelo was measuring the distance between the window and edge of frame to ensure the window was fixed vertically and was located at the desired place.

Picture 20. Angelo and Dean were nail the window onto the new plywood frame.

Picture 21. Kangping and Dean were measuring and marking the timber for stud construction.

Picture 22-23. Angelo, Feng and Dean were cutting the timber with drop saw.

Picture 24-25. Angelo, Kangping and Dean were assembling the timber structure with nail gun.

Picture 26. The finished timber structure was then nailed to the base plywood board.

Picture 27. The nogging was fixed to the timber studs and window was put into place.

Picture 28. The rest of the Hebel blocks were laid according to proposed design.

Picture 29. A piece of timber was fixed onto the top of the Hebel block wall as roof batten. And temporary bracing was put up to support the structure before the cement sets.

Picture 30. Kangping and Dean were measuring and cutting weatherboards.

Picture 31. Additional two timber members were put up next to the sides of window frame for weathers to be fixed onto.

Picture 32. Angelo and Feng were fixing weatherboards onto the timber frame with nails.

Picture 33. The front of the wall with weatherboards installed.

Picture 34. Angelo was cutting the corrugated roof sheet with disc grinder.

Picture 35. Holes were drilled and the corrugated roof sheet was fixed to the roof batten with nails. We overlapped the roof sheets to provide better protection from water.

Picture 36. Kaiping was sealing the gaps around the window with silicon.

Picture 37. The wall construction work was then finished. Temporary bracing was set up again to stabilize the wall. We can now wait for the cement and silicon to set so we can start the water test.

Note: As Feng Jiang was keeping a record of the construction process, she appears less frequently in the photos. However, all construction work was assigned evenly for each group member.

Hebel Research Part 4 (Installation)

Hebel Adhesive

Hebel blocks are laid using premixed Hebel Adhesive. The Hebel Adhesive should be prepared in accordance with the instructions on the packaging. Importantly, the adhesive should not be retempered as this will have a detrimental effect on the bond strength. After thoroughly mixing the adhesive is ready for use.

Installation of Blocks

All blocks should be brushed clean of dirt and loose particles. Hebel Adhesive is then applied to the vertical and horizontal surfaces using a Hebel trowel of the same width as the blocks. Vertical and horizontal joint thickness should be approximately 2-3mm. The consistency of the adhesive should be such that is flows easily through the teeth of the trowel. When applied, the ribs of adhesive should maintain their shape and not collapse. A thin mix will result in poor joint strength and is indicated by collapsing ribs. A dry mix will result in the ribs not bonding to the AAC surface and peeling off the block. The adhesive must cover the whole vertical and horizontal surface of the block to maintain wall strength, sound and fire rating. All perpends should be fully covered with the adhesive, made tight and a full contact achieved.

Excess adhesive should be removed from the block face as laying proceeds. The vertical joint of the lower course must be staggered at lease 100mm relative to the vertical joint of the overlaying course.

Horizontal Surface

Hebel does not recommend a horizontal surface finish of its products in external environments. As water could pond on the surface and penetrate the coating system. In the case of a horizontal finish, Hebel recommends that the surface be treated with a waterproof membrane or metal flashing/capping. The designer should ensure that the waterproof membrane is compatible with coatings, finishes, environment conditions, AAC substrate, etc. The main areas to detail correctly are roof and floor panels, window sills and the top of parapets. Importantly, the AAC substrate should be prepared in accordance with the membrane manufacturer’s instructions.

Figure. Hebel Installation Checklist

Construction Preparation

Here are a list of tools and materials we prepared to build the wall and their photos respectively.

Tools:

Picture 01. Tape Measure

Picture 02. Hand Saw (to cut Hebel Blocks)

Picture 03. Hammer

Picture 04. Disc Grinder (to cut corrugated roof sheet)

Picture 05. Nail Gun

Picture 06. Measuring Square

Picture 07. Drop Saw (to cut timber)

Picture 08. Basket and Water (for mixing mortar) 

Picture 09. Trowel (for laying mortar)

Construction Materials:

Picture 10. Hebel Block

Picture 11. Hebel Block

Picture 12. Window (recycled from hard waste)

Picture 13. Cement

Picture 14. Plywood (for window framing)

Picture 15. Plywood Detail

Picture 16. Plywood (as the base for wall construction)

Picture 17. Corrugated Roof Sheet

Picture 18. Timber MGP10 (as wall framing, recycled from hard waste)

Picture 19. Timber Unknown Type (as temporary bracing, also recycled from hard waste)

Note:

We have managed to recycle most of the construction materials through hard waste to achieve the goal we set to minimize material waste and the carbon footprint of the project. However, we were not able to get our hands on the Hebel adhesive as recommended by the Hebel manufacturer, it was then decided by the group to use concrete cement as a substitute.

Additionally, we did not get materials such as sarking, flashing and insulation. As these materials would not affect the structure integrity of the wall, the group decided to commence the wall construction, while we continued to search for the missing materials.