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As noted in another post on this Xtratherm CavityTherm is an (almost) full fill insulation system which incorporates a 5mm wide sheathing board on the front face. Therefore where 100mm Cavity =therm is specified you get 95mm of the PIR board + the 5mm sheathing. It has a conductivity value much...

Also builders might allow a small airspace between a cavity fill insulation and the outer leaf to stop the insulation pushing the outer leaf off bed when it is being brought up.

the U-values for the walls to extensions is unchanged at 0.28 W/m2K under the latest 2013 edition of Part L1/B. The only time lower wall U-values are required for extensions, is if the extension has a higher than the permitted amount of openings, in which case a calculation must be carried out...

Cavity therm consists of various thickness of PIR insulation board with a 5mm finned sheathing board that goes in front of it. Consequently when 100mm Xtratherm cavity therm is specified it is made up with 95mm PIR board and the 5mm sheathing. Reports from sites seem to indicate it can be a...

To satisfy the requirements of Approved Document E 2003, a separating (party) wall must have habitable spaces on both sides of it. There are currently no options for a composite party wall, where one side / part is formed in timber frame, and the other in masonry. Therefore Building Control are...

Silver sand was also used between floor joists and on top of lath and plaster ceilings as an inert sound deadening material. It is heavy (possibly too heavy for the size and depth of floor joits used these days in dwellings) and added mass to the ceiling, which helps to reduce the amount of low...

There are very often issues with cracking at the heads of openings, which are caused by several factors. 1. The wall panel above the head of a lower opening, and sill of a higher one, or at the top of a wall at roof level, represent a point of least cross sectional area in a wall, where any...

Jason - The `design life' for both timber frame buildings and masonry buildings was until recently given at circa 60 years, but the `design life' for masonry buildings was recently increased to 100 years. The inverted commas are because we know that this is a highly conservative estimate, and...

Aircrete blocks are manufactured in large cakes, which are then cut to the required block sizes using oscillating wires (a bit like the way wires are used to cut a block of cheese, or even those devices which are used to cut a boiled egg into slices) As the wires cut their way through the...

P.s as general rule, buildings should not be constructed nearer to a tree than its predicted mature height, but with building land becoming scarcer and more expensive, we are now building on sites that would have been avoided not so long ago because of issues like this. Even cutting adjacent...

Raft foundations are normally used where ground conditions mean that a traditional foundation or even a short bored pile system would be uneconomical. Typically where a suitable bearing strata is just too deep to reach. The depth of piled foundations can vary, and may be dictated by the size...

Where headers appear on brick elevations, this indicates that the wall is most likely to be a one brick (215mm wide) solid brick wall rather than a cavity wall. The front elevation at least has been built in Flemish bond (alternate headers and stretchers in the same course) The gable wall is a...

Surprised me at the time, but Approved Document C of the Building Regulations shows that a 215 mm minimum thickness block (either aircrete or medium density aggregate, but not dense aggregate blocks) can be used to build a direct rendered solid exposed wall in all parts of the UK (up to and...

Ask many people and they will tell you that the mortar joints between bricks, blocks stone etc are to `glue' them together. However the real reason for using mortar between masonry units is to keep them apart, and seal the gaps between them. Until relatively recently it was not possible to make...

VinnieG - Tony 1851 is correct regarding the width of a vertical crack. if it is of uniform width top to bottom, it is most likely to be a tension crack, At the foot of a wall movement `may / can' be arrested by the junction of the wall with the ground floor, which is why they sometimes do not...

Hi Ban all sheds. I guess I just meant on this particular topic, there are many on other subjects as you point out! Best Regards.

Hi Tony 1851 - you are right, it does seem as though postings here are fairly few and far between, but I thought I would just put my few pence worth in in case not, or if someone else might be thinking about building the same type of wall. Cheers!

Hi mise Blocks at 7.3 N/mm2, or stronger are deemed suitable for use in the freeze thaw conditions which are likely to occur at or below ground level (typically down to around 600 - 700mmm below ground. where ground temperature stabilizes at around + 4 degrees Celsius in the UK) Blocks...

Hi John - Yes. now very much dealing with the paperwork but was on the tools for 20 years and taught brick block work at a tech college for another 13 years.

John I deal with all block types not just aircrete, but I do know what blocks are best suited for different situations, including the requirements of the latest Building Regulations. There are a lot of myths and misconceptions about blocks of `all' types so just doing my best to spread the...