Thermalite brick

For a couple reasons including location/block size and a setup workshop at the back I want to keep my PPOR.

However I am steadily getting more and more issues with the thermalite brick. So I am debating on what to do.

Had a section of plaster give way above the stove so I stripped it back further for repairs. The attached picture shows the cracking in the brick itself and that is a section that is not supporting any major load. Load bearing sections such as above windows are worse. I would say about 40% of the plaster is floating loose, this winter it has really suddenly become a lot worse.

I am wondering if anyone has done anything like totally gut the inside walls of the house with roof in place and replace with timber frame?

Carpets and fittings internally are basically a write off due to age 10+ yrs. External walls are fine not a crack.

I have looked at selling but its a catch 22 of having to do at least some repairs 1st.

http://www.somersoft.com/forums/gallery/uploads/22073/Thermalite_brick.jpg

Do you know how it was constructed, IE soil test and what it showed, reactive, moderate or highly reactive soil? This would then indicate the footing requirements.

The blocks themselves I was under the impression they were glued together and then core filled with steel reinforcing, I have never used them my brother in sydney builds with something similar (different brand) .

When you tap the bricks are they hollow?

Look at this site or just type in Thermalite bricks
http://www.heidelbergcement.com/uk/...ormation/thermalite_technical_information.htm

Brian

I don't think footings are an issue. Inspected slab under lino and carpet in a 2 areas and no sign of cracks. Also as mentioned outside walls are fine.

The blocks are "solid" but extremely soft. Glued together and I am told there should be some "chicken wire" between some courses.
The only reinforcing is in the bigger lintel blocks above windows/doors. They have a number of 6mm rods. But it is mainly these that are breaking up and sagging.
The worse one was reinforced ~4years ago but given I can't get the door out of the runners again and the cracks it has obviously sagged since.

Long out of builders warranty before anyone suggests that.

I have been told that the blocks are borderline in their rating to support the weight of a tile roof. However this was just word of mouth so not something I could prove.

Maybe worth giving either the Australian Representative for the blocks or an engineer a call and see what they can come up with.

Not seeing the place bit hard to make a more informed call.

Brian

BGC don't care, far as they are concerned the 10 year warranty is up tough luck. Been down that avenue already previously.

This issue is not unique to my place. They stopped using the product due to the issues they were having. Most houses they just drywalled the internal walls and hoped it covered the issues to the guarantee ran out.

I was more seeking advice from anyone who has replaced internal walls.

Thermalite blocks have been used in the UK for decades. The key issue is that like all concrete products they shrink slightly over time until fully cured. This generally isn't a problem as long as factory-fresh blocks are not used (I have seen them being laid still warm) and as long as the mortar is weaker than the blocks so everything can move imperceptibly. In addition, longer walls need movement joints (often called expansion joints, but they are actually contraction joints). Lots more on this at http://www.heidelbergcement.com/uk/en/hanson/products/blocks/technical_information/thermalite_technical_information.htm.

Assuming that the cracking is due to block shrinkage and not foundation movement, it won't recur, so my instinct would be just to replaster.

Not sure if its a brick problem rather than the plasterboard adhesive failing.

Chomp

Tony3008 said:

Assuming that the cracking is due to block shrinkage and not foundation movement, it won't recur, so my instinct would be just to replaster.

Click to expand...

Some sections of the house have been done twice since I took ownership. I am assuming the previous owner must have also had it done at least once via BGC.
When the sliding door lintel collapsed the BGC rep let slip that he had previously been to the place when he commented about me having painted over the hot pink walls.
(Fluro pink walls, pink curtains, pink kitchen originally)

Chomp,
Its not plasterboard/drywall. That is what BGC used to hid a lot of the issues in other houses. "Wet plaster" as done in a standard double brick.

ah ok, so it is possible to replace the internal walls with timber framing, but it will be a pain.

I would check your foundations / footings first just to make sure otherwise you may replace the walls for nothing.

Im not sure how the price would compare but what about using grout injection?

http://www.masonrysolutions.com/publications/Injection.PDF

Chomp

Received some new information today. Have managed to get hold of some details on maintenance undertaken by the builder before I took possession.
Some notes are not very informative.

Built 1993.
21/2/94 - Repair cracks, kitchen, laundry, lounge, bathroom, hallway.
??/3/1994 - Major ceiling repair. Nails protruding through ceiling all rooms.
14/12/95 - Rear sliding door head bowed internal and external. Refix frame at jamb.
16/1/96 - Repair cracks throughout house.
??/??/96 - Repairs lintel Family room. 5 lintel cracks noted. 5 major cracks various rooms. 21 minor cracks.
15/2/1996 - Rear sliding door, lift door head and strap to top plate. Refix entry door frame to stop movement. Plaster to repair cracks.
28/5/1998 - Major cracks - repair + paint
29/1/1999 - Inspection - cracks
12/3/1999 - Repair S/door reveal.

2002 - purchased (no evidence of cracks)
2003 - BGC reinforce sliding door lintel with steel beam. Cracks repaired
2005 - Major repairs to lounge wall by plaster. Repairs to lintels plaster in most rooms.
2011 - Every room has cracks to various degrees. Most walls plaster "floating".

Gezz I really feel you need to go back to your building authority as I'm sure you are not the only one with is issue.

Push the issue with builder and WHO certified it (maybe government.

Thanks
Brian