MortarThePoint

We've got a single storey utility room at the side of the house and there is a section of brickwork wall above it. I was wondering whether the area shaded in red in the image below should to be brickwork of blockwork. This area is on the side of the main house. The SE have called for a movement joints between the external leaf blockwork and brickwork. This red area sits above the blockwork in the wall between the kitchen and the utility room. I guess the options are: Blockwork: if this is the case what should the expansion joint(s) be. Should there be a full height movement joint going up the left hand side of the red area and between the brickwork and blockwork above, as well as a movement joint on the right hand side of the red area? Is a movement joint not needed on the right (and in fact a bad idea) because the blockwork there is within the roof space and therefore not external. There is brickwork over the top of the blockwork and any possible movement joint on the right. Brickwork: I guess this would just be a full height movement joint going up the left hand side of the red area and between the brickwork and blockwork above. Blockwork is easier to install obviously.

Cool thanks. Does that go in at the rendering stage then? A product suggestion would be good as it always helps to see what the finished result looks like.

That looks really smart @nod , is that some kind of plastic strip either side of mastic?

Our design has some brickwork that adjoins rendered blockwork in the same elevation or at corners. The Structural Engineer has called for movement joints here: I presume that calls for the likes of the sleeved tie below, some form of foam strip and then a mastic seal on the outside. If that's correct, can anyone recommend a good foam strip to use (suggestion below) and give any guidance as what to look out for on installation? https://www.buildbase.co.uk/ancon-safetyended-movement-10367-2801192 https://www.buildbase.co.uk/fillcrete-brickfill-100x10mm-10351-2801693

Thanks, these look great. They look to develop a strength of 40MPa which is 40N/mm2 so close to C50 cement of the padstone and should be runny enough to flow or get pushed in. Wonder if I can get less than a 25kg bag as I'll need less than 1kg.

Runny structural grout sounds interesting. What sort of mix is that or is there a particular product I should look out for?

The challenge is a bed mix involves lifting one end of a 400kg beam. I could use an acrow I suppose.

Fair enough. As I say I love the look.

The widths are fine, it's the level and the gap that opens up that I'm wondering about.

I've been amazed by how expensive polished concrete floors are. I had our garage floor power floated and am pretty chuffed with how it looks for a day of graft and £350 for 60m2. I genuinely want to understand rather that just stock debate, but what can people be doing to warrant a £120/m2 price? The materials aren't any more expensive are they? Say it's 100m2, that's £12k. If two workers on £200 each a day, they should be there for at least 5 weeks solid to justify that price. I love the look so would like to understand why it is so expensive.

Structural Engineer designed it as a change from a different original design. The beam is ever so slighly wider than the padstones. The padstones are actually a 200mm wide, not ordered as such but that's what they ended up as. The SE was happy with the overhang and a 254 x 146 has less out of plane strength whilst also being deeper which was undesirable.

This beam looks spot on for level. Haven't check the other ones but expect OK.

Thanks PeterW. The beam is 4m clear span and currently not loaded other than self weight. Another beam of similar length has much less of a gap <=1mm. I had wondered about using stainless steel shims. They're not getting bolted down. I had asked the Structural Engineer a couple of weeks ago about that and he said that thermal expansion could cause masonry cracking so he wasn't a fan. The drawing says "END OF BEAM T BE FULLY ENCASED IN MASONRY, FILLING ALL VOIDS WITH RAMMED DRY PACK MORTAR". Is this the sort of void that's referring to?

How deep are the bores @ianfish ? I don't know what area you're looking to build over, but 8 seems like a lot. We had four sampled down to 5m, one of them went further but I can't remember how much. Percussive window sampling is pretty cool and you get to see what's down there and the lab analyses it in various ways. You get some instant results in the form of SPT data which is effectively how many knocks of the coring tool does it take to move a fixed distance (knocked by a known weight from known drop). You'll want to know the Plasticity Index as well, particularly if there are trees nearby. Careful with local knowledge as it's easy to be near a boundary like we are.

We've just installed some steel beams (UC 203x203x86). One padstone looks to be a bit out of level and across the 400mm opens up a gap of about 3 mm. Is this a worry? If so what should be done to fix it? For reference, the bottom flange of the beam is 20.5mm in height. The padstones are large and heavy (660x190x215, about 65kg) so getting them perfectly level would always be a challenge.

The tiredness is getting to me, a six month old and self building is a killer combo. Measuring an elevation drawing (at 1:50 scale) it has the chimney wall on the house side above the inner leaf of the house wall, not the outer leaf. Ignore the drawing in my last post. My comment was correct as it's referring to the blockwork of the chimney needing to align with the house wall outer leaf. Up to wallplate through, there shouldn't be any reason the chimney can't join the house's inner leaf as @Mr Punter suggests. I still need the PURPLE lintel to be strong to support the house wall outer leaf where it bears on it. Joining the chimney stack blockwork to the house inner leaf below first floor level would increase the load on the GREEN lintel a bit. Elevation View: Plan View:

It does seem more sensible doesn't it. I don't know why the Architect has insulation there. It would have to transition back to the Architect's plan at wall plate so that the wall of the chimney on the house side is back aligned with the outer leaf of the house wall. Otherwise the chimney would end up much squarer above roof level than originally planned. That would involve some lintels at wall plate level though which doesn't seem an issue. I have shown the outside edges of the chimney brickwork above roof level in RED:

I'm increasing thinking the insulation between the house and the chimney is pointless and results in a lot of complications.

Its always struck me as a bit nuts that the chimney stack inner blockwork is insulated from the house. That's how the Architect designed it. It would take a lot of load off the PURPLE lintel if that blockwork tied in to the house inner leaf.

One thing I am not so keen on is the PURPLE lintel bears on a 100mm wide wall effectively. It must be stabilised a lot by the corner with the 140mm blockwork, but it's always nice to think of something bearing on a fat wall. The bearing itself can be improved by widening the wall slightly as shown below.

I described the setup and gave some of the images to lintel suppliers. I shared more about my thoughts on the GREEN lintel, but didn't want to 'lead the witness' on the PURPLE lintel so just shared images and load numbers. For the GREEN lintel, one supplier said a 140w x 140h lintel would be OK, whilst another recommended a 140w x 215h lintel saying it would triangulate, but did his calculations based on it not to be on the safe side. For the PURPLE lintel, the same first supplier recommended a 100w x 215h lintel and the other said to consult a Structural Engineer.

I know what you mean there, but I tried to get the Structural Engineer to do it all at first and then did it my self out of despiration. I should have said he didn't show much interest in the whole area.

I'm a bit nervous to share this post, but hopefully people will think the design sensible. I designed most of it and I'm not a Structural Engineer so here's hoping I've not made a massive mistake. From the Architect: The design calls for a chimney breast that narrows from 2409mm to 1228mm width. The fireplace opening is 1805mm wide and 1200mm above finished floor, 1125mm above top of hearth. The Flue Arrangement To avoid complex corbelling, discussions with the brickie about how all that is done as well as to allow brickwork to come up, I have decided to make the offset in twin wall flue (i.e. Schiedel ICID). It's a bit nuts, but the flue arrangement is single wall vitreous to twin wall flue to Isokern pumice. Considering the labour etc, the twin wall doesn't actually add much cost and looked to solve a lot of problems. It means the Isokern flue is entirely vertical and can start much higher up. I checked with Schiedel as well as our intended HETAS installer that this is technically possible. Granular fill: I could create a smaller box out of blockwork to be filled with the ganular material (Leca or a perlite substitute) but that would either need much longer ties or increase weight of blockwork. The plan is to construct as in the Architect's drawing and use lots of granular fill. The Lintel Arrangement Well if you thought the flue was complex, there's quite a nest of lintels. House Inner Leaf Lintel: Above that opening there will be a concrete lintel which will be timber dressed. This concrete lintel will be the same width as the house wall inner leaf that it bears on which is 140mm. I chosen to treat it as only bearing on the blockwork rather than the brickwork that actually defines the edge of the reveal. The gap in blockwork is 100mm wider on each side than the fireplace opening, so 2000mm. I calculated the loading on this lintel under two different assumptions: 1) It does triangulate: assuming the blockwork forms an arching action and so I can consider everything in a 60 degree triangle above the lintel. Unfortunately the floor does intersect this triangle so I needed to consider the load from that. The two loads to add are the weight of the 60 degree blockwork triangle and the load from a section of floor bearing the same width as the width of the triangle at that height. Below is the calculation I did. The eagle eyed among you may notice I haven't included the lintel self weight, but that shouldn't tip the balance much. Floor loads from the Structural Engineer's original calculations. 2) It doesn't triangulate: should there be no arching action. I drew a rectangle above the lintel up to and including the floor, but no higher. The maths is much easier: The wall creates a UDL of 1.275m * 0.14m * 1450kg/m3 * 10N/kg = 2.6 kN/m The floor UDL is (4.710kN/m2 + (0.9 * 3.700kN/m2)) * (4.2m / 2) = 16.9 kN/m [4.2m is the floor span] TOTAL UDL: 2.6kN/m + 16.9kN/m = 19.5 kN/m Apparently the rule of thumb is that if the window is over 600mm from the opening then it can be neglected and assumed to triangulate. The distance is 630mm, so I wanted to consider both cases. There are various lintels that could be used to meet the requirement. Some lintels are on crazy lead times these days, but I have chosen a Supreme R21240 which, when used the 21A orientation 140w x 215h), has a load capacity of 47.40 kN/m. Deflection at 1/3 capacity (15.8 kN/m) is 3.41mm, so deflection at 19.5kN/m should be 4.2mm. The triangulated case could perhaps have been met by an R15240 in R15 orientation (140x x 100h) with load capacity of 9.92 kN/m, but I wanted to go beyond that and fancied the R60 fire rating of the R21 lintel. Stack Lintels: this is much more complicated as there are various loads to consider. There need to be lintels at right angles to support the inner leaf of the chimney stack. The main lintel (PURPLE) has to support lintels all these lintels as well as a section of the house's outer leaf brickwork. [NOTE: the GREEN lintel is the one considered above] Listing all the loads on the PURPLE lintel from left to right: 0 to 1805mm : 100mm blockwork, 385mm high (BLUE) : UDL 0.56 kN/m = (0.1m*0.385m*10N/kg*1450kg/m3) 0 to 881mm : house outerleaf brickwork (ORANGE) : UDL 5.78 kN/m = (0.1m*3.5m*10N/kg*1650kg/m3) at 927mm : left hand lintel that supports outer leaf brickwork return : point load 3.12 kN = (0.1m*0.631m*6m*10N/kg*1650kg/m3) / 2 at 1126mm : lintel bearing that supports the side of the stack inner blockwork (GREY): point load 2.74 kN = (0.1m*0.624m*6m*10N/kg*1450kg/m3) / 2 at 1273mm : lintel bearing half the weight of the flue liner and surrounding granular fill : point load 2.28 kN = (9.1kN / 2) / 2 1176mm to 1805mm : stack inner blockwork (GREY) : UDL 8.7 kN/m = (0.1m*6m*10N/kg*1450kg/m3) at 1713mm : lintel bearing other half of the weight of the flue liner and surrounding granular fill* : point load 2.28 kN = (9.1kN / 2) / 2 * weight of flue liner and granular fill: weight of liner : 1.1kN = ((11kg/unit * 6m * 10N /kg) / (0.6m/unit)) weight of granular fill : 8 kN = (0.429m*0.624m*6m*500kg/m3*10N/kg) [assumed 500kg/m, Leca seems to be about 400kg/m3 I think] TOTAL : 9.1 kN = (1.1kN+8kN) Total load on lintel: 22.0 kN = ((0.56*1.805) + (5.78*0.881) + 3.12 + 2.74 + 2.28 + (8.7*0.629) + 2.28) Quick worst case calculation by putting full load at lintel mid-span. The maximum moment from a point load mid-span is double the moment of the same load spread as a UDL I believe. Therefore equivalent UDL is 24.4kN/m = (22.0kN * 2 / 1.805m) That's a bit scary! A more considered calculation: I want an equivalent UDL loading to compare with lintel specifications. A UDL across a beam has a maximum bending moment of M_max = q * L2 / 8 . rearranging gives q = M_max * 8 / L2 . Putting in the maximum moment from BeamGuru gives q = 5.32kNm * 8 / (1.805m*1.805m) = 13.1 kN/m. That's much better ? A 2100mm Naylor R9 lintel has a stated Allowable Load of 25.78 kN/m with 1800mm free span. This is very nearly double what is calculated here. I expect there would be some load spreading onto surrounding walls as well reducing the loading on the lintel, but I don't understand all the mechanics of that, so have tried to keep the calculation worst case. There would be some load spread by the blockwork between the BLUE lintels and the PURPLE one, but I wanted to consider the case similar to not having that blockwork. I might repeat the calculation assuming 45 degree load spreading under the BLUE lintels. These lintels have short free spans (424mm) and are chosen to match masonry of help support the flue base. The Structural Engineer hasn't shown much interest in all this when I have tried to get him to take a look. Tools: QCAD, OnShape, BeamGuru.com

I'm writing a big post about all my chimney and flue design journey which has been a bit involved to say the least

Cool, thanks