Advice on building wall

[Pangloss]

Hi everyone I’m new to the site, so please bear with me while ai get my bearings.

Here’s my issue: I am building a new wall in concrete blocks abutting an existing wall one on one side and with a return on the other. The new wall will be only 2.1M wide and will have a doorway through it. The side abutting the existing wall will be only one block in width (44 cm). Cutting out the existing wall in order to key in the blocks is my last option as in the opposite side of the existing wall is a layer of 50mm insulated plasterboard and I’d prefer not to disturb it. I’m not happy (or convinced) that the L shaped wall ties are adequate for tying the new wall to old. A further thought is to use the wall starter system with the flexibility of tying in any out of sync block work. First of all, which is the best route to go down? Second, as this section of wall is just one block in with, can the blocks just be stacked on one another to the point at which the lintel bridges the dooway opening? It seems intuitively wrong to do this, but it also seems futile to half blocks just to mortar them back together again to show a bond. Your advice on how to deal with this would be most appreciated.

Thanks in anticipation

[moderator7]

I've moved this to the building forum.

[Pangloss]

Thank you Mod 7

[mick.mh2racing]

Starter wall ties are fine but expensive. I wouldn't be toothing out any block work either, Screwfix sell wall ties that you drill and screw to masonry, I'd use those.
I'm terms of cutting your blocks, do it. I wouldn't build any wall lower than 2 courses high without one. Yours is too high and won't be strong enough, you could probably push it over.

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[Pangloss]

Thanks for your prompt reply Mick.

I just noticed a typo with my original post. It should have read “width”, and not “with”!

I understand the weakness issue just stacking blocks.

So although the wall section is just a single block in width perpendicular to the existing wall, making alternate courses one whole block and then two half blocks (minus 10mm for the mortar) is stronger than stacked blocks?

[mick.mh2racing]

Yes, I'd definitely say so. Never noticed your typo to be honest.
If you built a wall without a bond, let it go off for a week and then have it a study shove I reckon you'd have it over.
You understand what stretcher bond is? Half of block overlapping a full block on the course below? Much stronger.
Check out these walk ties.
https://www.screwfix.com/p/sabrefix-scr ... pack/31633
They'll hold a wall to another wall.

sent using smoke signals

[Pangloss]

Thanks again for your reply Mick.

Yes, I am familiar with stretcher bond and one or two orhers. Under what we could consider a “normal” situation, I realise the load sharing through bonding, as it makes its way down through the wall and via the floor/foundations to the ground. However, in this situation there is no “triangle” for the forces to be dissipated through. The blocks, bonded on alternate courses and sitting on a whole block, simply transfer the load across 440mmx100mm and then down through each successive course. Tying this construction to the adjacent wall would not change the loading characteristics. In this scenario, wall ties play an insignificant role, if any, in load sharing, they are there to try and mitigate the lateral forces through, say, the rotation of a heavy door, or someone leaning something heavy against it.

Were there three or four blocks per course, I would perfectly understand the situation and would not have posted my queries.

Food for thought.

[mick.mh2racing]

Just how high is this wall? You mention a door way so I assumed wall would be over 2m.
When I asked if you knew what stretcher bond I didn't mean to patronise you, I assumed given the question you asked your skill level was reasonably low when it clearly isn't.
I know what I'd do but you decide what you want to do for self mate.

sent using smoke signals

[mick.mh2racing]

Do you know, I might have miss read your post. How long is the wall?

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[Pangloss]

Morning Mick,

No need to apologize, It is better to assume little knowledge in situations like this, besides, I should have made it clearer to begin with.

I’m in the process of rectifying a dogs breakfast of a build that was almost complete before it was abandoned. The space allocated for a downstairs bedroom had a doorway located in an odd position, and so having removed and replaced a number of walls both Load bearing and partition walls, I need to reinstate a section that is 2.22M wide. This equates to two blocks in the one side, keyed into a new return wall; a dooway; and only one block on the other side of the dooway which abuts the living room wall. As much as I am loath to do so, I can see no alternative but to key this short section every other block as it rises, and the use closers for the corresponding gaps where the door frame will fit. I am quite adept at using hand tools in order to be neat, but given that the internal render is as hard as I’ve ever come across (no browning and skim on this one), I will invariably damage to insulation on the wall I’m keying I to.

Starter ties may well be adequate for the job, but I have a feeling in my water, that they won’t be, even after the completed wall I’d loaded. I’ve even contemplated chasing out the mortar and using the long L shaped gable end wall ties through the existing wall and cementing them in at each corse. This however also means sacrificing the insulation and again having to deal with the mortar which is harder than the existing concrete blocks. I always prefer the most delicate approach to solving problems, it is looking more and more like an angle grinder and plugging chisel is the only way to go with this one!

It has been good if you to continue to respond Mick, I appreciate it. The job so far has been a real challenge; one problem solved has led to two more to deal with. A new build would have been completed in the time I’ve spent thinking through and resolving the issues with this one.

Cheers, Alex

[mick.mh2racing]

I get it, so your original question about bonding, you've answered yourself and will be fine.
Any and every job I've ever done is always a case of solving one issue to create two more so you've always got to just do the loading front of you as best you can. Thinking ahead is fine but there's always something you'll forget to account for.
Good luck.

sent using smoke signals