Dot and Dab is Dead, Love Live Dab ..

For all of you out there that have not seen me draw this for you at a test as a best practice, here you go with my poor handwriting.

For those of you that can't read my jibberish ...

• Continuous vertical bead from floor to ceiling
• Continuous horizantal bead wall to wall as close to perimeter as possible
• Single oval bead covering the majority of the sheet for each
• Bead around each plumbing / electrical / television / telephone /Sky etc. point
• Wrap your beads on horizantals to connect through corners
• Additional beads / dabs / dots as necassary to hold drywall to wall

Or to make it even simpler, just use wet plaster everywhere.

BTW, that is a radiator on the wall in the centre  a light switch on the wall, and a few plugs lower down with their wires and plumbing snaking around. The oval tends to cover these up and by putting the horizontal bead  near the perimeter, you are better able to tie in the floor and wall / ceiling.

For more information or to book a test, call me on 01484 686649 or visit my website on
http://www.hometestingyorkshire.co.uk/

I hope this helps,

Thanks,

Matt

Shadow Boxes ... The wrong way and the right way

Right, I was asked to post more on Shadow Boxes and the way the issues presented themselves, and what could have been done to alleviate them. so I have done some hand drawings with my terrible handwriting added to the mix.  Hope you can read them and make things out.

Below we have a Shadow  Box and how it presents itself in a room when installed. Basically it does a cut out of a box into the base of the floor and uses the shadow created by the light hitting the top surface to make a dark shadow. They look extremely nice when installed and are commonly found in art galleries and the like as they compliment modern homes and décor quite well.

When I tested the house in question for my client, she complained that their house had gone from being a relatively warm house to downright cold after the builders had left. The intention was to add Kingspan internally on wooden battens that would be attached to the existing breeze block and as well to have a Shadow Box put in instead of skirting boards as they liked the look. Fair enough, they had the money to spend, they had the right decor, and they were looking to save money on energy costs with the added insulation.

What they ended up with was a gaping hole through to the cavity via the joists, chipboard, and any other penetrations running throughout the house. If you have ever read this blog, you know that air flow in the cavity, in the attic cold air space, and under the floors around the joists is expected and necessary to keep things right in your home.  The air barrier should be after the cavity and before the internal surface of the dwelling. This house went from having a decent air barrier to having an area equal roughly to the surface area of the shadow box multiplied by the total perimeter or the homes exterior and interior rooms.  Let's just say, it was impossible to get it up to 50 Pascals of pressure and that was with closing all the doors in the house! It was like every window in their house was open all the time even when every window was closed.

Anyway, here is a depiction of the top and side views of the installed walls:

As you can see the pathways for the air allowed anything in the cavity, or floor spaces to bring air into the home via the space left for the Shadow Box.

Two simple additions to this and a bit of tidier behind the scenes adjustments would have made this whole situation better.  As you can see in the drawing above from the side view, it is very rough where the floor coverings don't meet the exposed breeze block, and the underside of the wall allows the Kingspan and battens to be exposed.  In the following drawings you can see how this could have been alleviated by putting a simple parge coat over the exposed breeze block, foaming the join between the chipboard and the wall, and then putting an extra batten attached by an L bracket (or even screwed in if it would work) then applying  drywall to those surfaces prior to putting on the Kingspan and vertical drywall for the finish.

For more information or to book a test, call me on 01484 686649 or visit my website on http://www.hometestingyorkshire.co.uk/

I hope this helps,

Thanks,

Matt

Shadow Box instead of skirting boards ...

Don't do it unless you call me first please. Can't say much more as there is a bit of bother going on with this topic ...

Matt

How much air pressure?

During an air test, we're allowed to de-pressurize or pressurize your dwelling by up to 100 Pa or Pascals. Now, common questions I have is, "Will I die?","Is my dog going to be okay?", "Will it break my China?".


The answers are no, yes, and no. All this test does is make you bald and fat after doing a thousand or so. See below :) 

So, say we apply 100 Pa to your dwelling / house. What can you compare this to?  Well, One atmosphere is 101,325 Pa, and that means that if the barometric pressure outside is high, 1024 or so, and I de-pressurize it by 100 Pa, then it is still going to 1024 :) Applying this another way, on a 400 cubic meter house (typicalish in the UK), I would be applying 400 * 25 pounds of pressure or 100 pounds of pressure to the house.  If you compare this to the change of barometric pressure, when it moves from 1023 to 1024, it is applying 1,042,500 pounds of pressure on your house.  By the way, this happens all the time, and barometric pressure can swing 10 bars in a day or 10 million pounds of pressure across 24 hours if not more.


Now, some mathematical genius is going to come along and dispute these figures, but the truth of the matter is, you really aren't going to notice a change in your house by my dinky little old fan in your door.  
I hope this helps,

Matt

For more information or to book a test, call me on 0793 091 5595 or visit my website on http://www.hometestingyorkshire.co.uk/

How big is the hole?

For three years I've been trying to figure this one out! When I do an air test on a house, I wanted to get the EqLA or Equivalent Leakage Area of what all the holes, added up, were in that house.

I have the formula now from Retrotec and while it isn't simple, and you'd have to have the kit I own to get the answer, there is a way to tell my clients that they have a hole 10 cm by X cm.  This allows them to visualise the total unintentional leakage in their home.

EqLA = ( roh_air / 2 ) ^ 0.5 * Cenv * P ^ ( n - 0.5 ) / 0.61

It does work out on Excel quite well, but you have to know the Air Flow Coefficient, and the Air Flow Exponent.  It also assumes that the air density is constant and you could apply your Correlation Coefficient to give a degree of confidence but that isn't included in the above formula.

If you'd like a better explanation, please contact me or leave a comment below.

Basically, I have been intrigued to find that most homes recently tested have had a cumulative unintentional leakage area that is over 1000 cm2

Thanks,

Matt

http://www.hometestingyorkshire.co.uk/

Condensation in upper floor rooms

We've talked about condensation in upper floor rooms before, but recently I have been seeing this quite often in existing homes. I would encourage you to look into either Passive Input Ventilation or changing your ventilation techniques.

A recent enquiry was from a landlord who has a tenant that doesn't put the heat on, dries their clothes internally, and is a bit of a shut-in.  This all adds up to increased condensation and mildew. Now, the tenant isn't going to change for the benefit of the landlord, so he will be forced to take action.  When talking to the landlord, he says that he has not had this problem before.

For about £250 plus installation, Nuair have a product called a Dri-Master 2000 that fits the bill. Simple to install, and a doddle to maintain.  Give Julian Cyprien a call on 07767298195 to arrange a sales call with him.  He's a decent guy and will be able to give you the specifics of the system to see if it is right for you.

For more information or to book a test, call me on 01484 686649 or visit my website on http://www.hometestingyorkshire.co.uk

I hope this helps,

Matt

MVHR requires a low air tightness score

Just think, if you kept pouring water into a colander and expected it to ever fill up, that's what it's like putting an MVHR system in your house and expecting it to heat up when it is full of holes.  


I've recently been testing quite a few houses and apartments with Mechanical Ventilation Heat Recovery (MVHR) systems in them.  Most are doing okay for the regulations and meeting their Design Air Permeability. Only one set of apartments that I've done recently has been below 4 m3/(h.m2) which is probably starting to get to the optimum range, the lower the better by the way. 


Most are getting around 8 m3/(h.m2) and this is not benefiting the user of the system. The intention of these types of systems is to exchange the heat, ventilate the home, and save energy versus gas or electric heating systems. If you are only giving the system cold outside air to work with, it's going to have to work much harder to give the same benefit compared to an airtight house. 


So, if you have stumbled across this blog because you're having problems with your MVHR system not working to its optimum performance, maybe you should get your house looked at by someone like me. We can highlight where things are going bad, and improve your system performance significantly. 


I hope that this helps you along the way.


Matt


www.hometestingyorkshire.co.uk

Green Investment Bank to be located in Leeds

The Green Investment Bank that the coalition government is proposing could be based in Leeds if you believe all of the posturing that went on today in Parliament. MPs from the region put up a good argument and we will have to see what happens, but with Leeds being the second largest financial sector in the country, if not Europe, it should be a no-brainer.

Code for Sustainable Homes

Code is getting to be a hit or miss affair for each planning department around the country barring London, where you have no choice. I know in my neck of the woods, only Manchester City, and Harrogate councils are adamant about it.  If they want to give you a hard time, some planners will insist on it in various councils around the Yorkshire area.

Went to a CPD session yesterday on sustainability.  It was good to see how the big boys do things and how we can offer a tighter service for our customers by being a bit more customer focussed. Sometimes it is nice to be the little guy.

I think what I should tell you based on the session is that even though some of the points on the Code seem easy to get, you really have to keep in mind that there are several considerations for each instance.  For example, the bike storage.  On the face of it, give them a place to park a bike and they should be happy right?  Well, if you do it in your garage and give them the required space, then it is fine. Try to do it outside in a shed and it becomes a whole another kettle of fish.

One other thing I gathered from the day was that the Code is really government preparing the industry for the regulations.  I never really grasped that aspect before.  If you look at Part L1A and how the energy requirements in 2010 are 25% improved over the last set, then look at Code level 3 and it is 25% improved over the same requirements for energy, you can see where this is going to go as new iterations of the building control regulations come about.

Call us and we can walk you through the issues and the concerns that you might be having.

How do you test?

When testing a house, we are generally sucking air from outside to the inside and passing it across the fan in a frame that has sensors around the house and outside, where we are measuring the change in pascals, or a very small unit of barametric pressure. The equipment is rather sensitive, and includes the use of a micronometer and a highly calibrated, adjustable, and powerful fan.

As you can see in the picture, we take into account the current conditions by taking readings before and after the test for things like time and date, barometric pressure, wind speed, baselines for pressure differences internally and externally, temperature, elevation, and envelope size.

The 8 to 10 readings of the test are then entered into a proprietory software package and the output is a score that tells the unintentional leakage score for your property. This takes into account the intentional leakage points like extractor vents where we have taped them up for the test. For the test to be valid, the baseline readings need to be within tolerance, which usually means that the wind speed does not exceed 13 mph. As well, the slope for the readings, gap between the readings, and any deviations need to be acceptable.

A new house in the UK is required to score at most, a maximum of 10 cubic meters squared per hour at 50 pascals. This equates to about a 10p piece (25c or quarter in the US) hole per m3 of the envelope. So, if you have a property where the envelope is 300m3, you are allowed a 'hole' in your house 1 foot by 2 foot. When you take into account all of the places that leaks can occur, this really is a low tolerance level and this is just for a marginal pass with the largest margin for error.

The overall test takes about 2 hours from start to finish. This takes into account all of the factors above and generating the report, printing the certificates, wrangling the cheque from your hands, finishing the coffee you were so kind to offer ... :)


I hope this helps :)