Construct Ireland Stephen Young

8/9/2019 Construct Ireland Stephen Young

1/8


2/8

Forwardpass

LOUTH HOME MIXES WIND,SOLAR & GREEN MATERIALS

WITH PASSIVE AMBITIONS

Photos:David

Ruffles


3/8

CI 37

As interest in sustainablebuilding continues to esca-late, Construct Ireland is in-creasingly unearthing buildingsthat betray an ambition tobreak new ground under aplethora of green criteria.John Hearne visited one suchhouse in County Louth, andfound a project driven bypassive house and BER scale-topping ambitions combinedwith on-site energy and watersupply strategies and a com-mitment to the use of greenmaterials.

A new house inCollon, CountyLouth marries pas-sive house princi-

ples with anaesthetic that sac-rifices nothing tolow energy design.Superinsulation, avery high level of

air-tightness and a selection of renew-able technologies facilitate a dispersed,tiered layout that works perfectly withthe site and the surrounding country-side. The house itself came from the to-pography of the site, says StephenYoung of Young Design Build, the homes

designer and owner. Because of its heightand the location, the site didnt lend itselfto two storeys or anything of that type,which would have been more suitable forpassive house.

The passive house standard, as with alllow energy design, is predicated on sim-plicity. Complex architectural shapesthat are difficult to heat or compromiseair-tightness are out. But by taking an in-

novative approach to construction andmaking maximum use of orientation,Stephen Young has effectively delivered apassive house with a twist. We ended upusing the tiers on the site and came upwith three different blocks, separatingour living areas from our sleeping quar-ters with a corridor in between, to giveus a U-shaped block with a courtyard tothe centre.

Because of that dispersed footprint,achieving low energy consumption was abit more challenging, admits young. It wasachieved primarily by reducing heat transferthrough the building fabric surpassingeven passive house criteria. We wentfrom the standard 0.15 W/m2K down to

0.12 W/m2K he says. 0.15 W/m2K wouldbe an average requirement for the wholeenvelope, so we got 0.10 on the floorsand 0.12 on the walls and the roof. Inaddition, glazing on the northern faadewas kept to an absolute minimum whilemaximum advantage was taken of the south-ern aspect. Using smoked glass panels inconjunction with the U-shape, even bed-rooms with a northern aspect enjoy con-siderable passive solar gains. In fact, thebathroom and the utility room are theonly rooms in the house that dont get

any southern light.

We used strip foundations because ofthe change in levels between the differ-ent blocks. The site or the design didntlend itself to an insulated raft slab, sowe went with strip foundations and usedQuinn-lite block work for all the risingwalls. Its an aerated block, so its gotbetter thermal efficiency than a standardblock. Its a structural block as well; very

light and easy to work with.

One of the stand-out elements of thebuild was the innovative I-joist timberframe. Typically only used for structuralpurposes on long spans, Young came upwith this solution in order to achieve adeeper structure and thereby facilitate agreater volume of insulation. We lookedat lots of different methods of construc-tion to achieve high U-values with re-duced depths, so I could have a timberstructure that had less of a thermalbridge from the inside to the outside,which meant we could use less insula-tion. We used two elements of soft wood,internally and externally, which are con-nected by a plywood web. The plywood

webbing, from outside to inside, reducesfrom a width of 50mm down to 9mm, therebydrastically reducing the heat transfer.

Stephen came to us asking if wed beable to make walls out of I-Joists, saysConor Doherty of A-Frame Energy Effi-cient Homes. We looked at his floorplan, got our engineer to review it andsaid basically, yes, we could do itYourstandard walls are 140mm, and you justpack in the insulation. With the I-joists,you can go as wide as 400mm, and

(opposite) The cedar clad front of the newly-built house; (below) the southern aspect of the house utilises extensive glazing to max-imise passive solar gains


4/8

you can also get spans of 6m and 7mlong. Young also points out that byachieving a high thermal performance inthat one single solution wider walls youre reducing construction time andexpense. Theres no need for additionalthermal measures, either outside or inside.The frame also comes pre-fitted with aSolitex external breather membrane fromEcological Building Systems to protectagainst moisture ingress. In all, the timber

frame took two and a half days to go up.

Next came the air-tightness membrane.Here, Young chose Sigas Majpell breath-able vapour control barrier, used in con-junction with Sigas range of tapes andadhesives. Andreas Schmidt of Siga iskeen to point out that achieving air-tight-ness is as much about process as prod-uct. Training is crucial in securing theexacting air-tightness standards requiredwhen building to the passive house stan-dard. To that end, Siga run a one-daytraining course for customers, then backthis up with advice and site visits as re-quired. Our products are very good, butwithout good workmanship, theyre worthnothing, so you need that kind of train-

ing and advice onsite. In conventionalbuilds, the membrane is typically stapledon. In passive construction however, itsrecommended that tapes are used to re-duce penetrations through the membrane.Quality control was also a big aspect.says Stephen Young. All trades onsite weretaken through the air-tightness processto drive home the importance of keepingit intact throughout the build. The wallbuild-up also included a service cavitythrough which cabling and plumbing wererouted, again in order to keep servicesaway from the membrane. According toYoung, air-tightness tests recorded anastonishingly low 0.235 air changes perhour at 50 Pascals, substantially better

than the passive house 0.6 requirement.

Into the frame went no less than five tonnesof Warmcell 500, supplied by Ian Fox ofCollon Eco Insulation. We were given anapproximate start date. says Fox, butunusually for this business, the Youngswere ready ahead of time by roughly twoweeks. We were able to work to the newdates and found the site meticulouslyprepared. All of the breathable membranewas erected without any creases or sagging.

Internally, Young considered standardplasterboard but opted in the end forFermacell building board, primarily be-cause the product removes the need for

skim coat. A conventional plaster finishintroduces a substantial amount of waterinto the build, leading to the likelihoodof cracking as the finish dries out. Fer-macell is however finished with FST, a light,trowel-on finish that can be paintedwithin half an hour of treatment. Its afibre board as opposed to a plaster board.says Paul Callan of Richmond BuildingProducts, who supplied the material.Manufactured from water, recycled paperand recycled gypsum, its high density givesit high fire and acoustic ratings. For ex-ample, 12.5mm board on either side of a75mm metal stud, with a rockwool infill,can give you up to 54db sound reduction,and that outperforms 9 inch blockwork.Fermacell also substantially outperformsplasterboard on racking strength. Equiv-alent to 9mm plywood, the board cantake up to 50Kg from a single point load-ing. Its also moisture resistant and can


5/8

CI 39

be used in bathroom and kitchen areas.

The full wall build-up is as follows: Fer-macell, a battened service cavity, the air-tightness membrane, the timber framewith cellulose insulation, an external rackingboard, breather membrane and externalbattening. For outside finishes, Youngchose a mix of render finish and cedarcladding, delivering an immensely im-pressive total wall U-value of 0.12 W/m2K.

I-joist construction with a cellulose infillwas also used in the roof, maintainingthat same U-value. Though Young had in-tended finishing the roof in zinc, theplanners insisted on slate. This presenteda particular problem because of the lowpitch of the roof. The plan specified a 10degree pitch, but slate cant be relied uponto withstand wind-driven rain when thepitch drops below 20 degrees. The choicewas then either to increase the pitch, orfind another way to weather-proof. Youngchose the latter. Above the breathermembrane, he battened and counterbat-tened, then installed a Kingspan insula-tion panel, but for more than its thermalproperties. The panel provides protection

against the elements, while the air cavityunderneath prevents condensation buildup. A Nu-Lok slate system, also providedby Richmond Building Products, wasthen fitted to the top of the panel. Byusing the Nu-Lok system, Declan Greenof Richmond explains, you set out yourbattens at 307mm apart, and theres alinking channel for every tile. You fit 8.1tiles per square metre. Because the linkchannel works as an overlapping system,you dont have to use as many tiles persquare metre. In addition to the costsaving and environmental benefit sim-ply by reducing the usage of materials it also places less stress on the timberframe and the foundations. Its a more

secure way of fixing your roof and its aquick and easy way to work. It cuts downon labour and youre not nailing the tilesbecause youre just clipping them intothe link channel.

To complete the envelope, Young installed200mm of Xtratherm rigid polystyrene inthe floor, underneath a 150mm floorslab. Then, instead of additional interiorfinishes, he polished the concrete slab.There were two reasons for that, hesays. We really liked the finish when wesaw it elsewhere. Its a hard, durable sur-face that youve no worries about main-taining; its like one big floor tile really,and the pure look contrasts well with the

white walls. Plus we wanted to maintainthat heat sink as well.

The triple-glazed, aluclad doors and win-dows are from the Edition range from Inter-norm, supplied by Ecoglaze. When wefirst went looking at windows, we foundthat some companies had great U-valueson their windows but they wouldnt do acomplementary door or a complemen-tary sliding window. We wanted every-thing to tie in together; that was onebenefit of the Ecoglaze range. And theexternal window sills came as part of thesystem they clicked in underneath.Each window incorporates three 4mmglass panes with argon fills and alu-minium spacer bars, while the energyperformance is further enhanced by thethermal break that the external claddingprovides. The total U-value in the win-dow comes in at 0.86 W/m2K. This falls

(opposite, top) the single storey house is tiered to fit in with the sloping site; (bottom)high performance triple glazed windows sit in a substantially thick wall; (above) threesolar panels are mounted on the roof; (below) LEDs are fitted in the hall


6/8

CI 41

short of the passive house target of 0.8W/m2K, but because walls and roof out-perform the criteria, the overall enveloperemains within the specified limits. Thedoor that Stephen went for in the frontof his house is a passive house standarddoor, says Matt Jordan of Ecoglaze. Itsgot a total U-value of 0.79 W/m2K. Itssuch a big unit, it feels like a safe whenyou open and close it. Does the size andweight of these units, and the chunki-

ness of the profile ever put people off?The only problem, he says is yourerestricted to certain designs and theyrefairly European designs, so for the pas-sive house door you wouldnt get thelikes of Georgian doors in Dublin.

One of the key advantages of the Ecoglazepatio doors is that they tilt and turn, fa-cilitating summer ventilation. Young alsohopes to deal with any overheating is-sues with planting. I didnt really likethe idea of integrating louvers or any-thing like that into the building, I dontthink they look residential, and given thesize of the house, large overhangs wouldnthave worked either, so were looking atintegrating natural solar shading by

planting a lot of trees.

In keeping with the best low energy de-sign principals, the three bedrooms onthe houses northern elevation have smallwindows. However, they still manage tobenefit from considerable solar gain. Allthree open onto the hallway which con-nects the houses two tiered blocks, whichis itself south-facing and features largeglazed sections. Smoked glass panels fit-ted alongside bedroom doors conduct muchof that passive heat into the bedrooms.

The houses sole space heating source, aKal-Fire wood fire, was imported directfrom the manufacturer in Holland. Its a

partially sealed unit, fronted by a glasspanel, which, crucially, has its own airsupply ducted directly to the fire fromthe outside. The amount of air going incan be adjusted to temper combustionintensity. Because its glass enclosed,says Young, its far more efficient, so itburns more slowly. Its a smart unit inthat once you have it burning, its got itsair supply to the underside which it dis-tributes in two ways. First into the com-bustion area, then the other air supplygoes around the casing of the fireplace.That heated air is then conducted intothe living space through vents on eitherside of the fireplace.

The one disadvantage arising from thecombination of wood fire and the low airchange rate is that you cannot use theextractor fan over the cooker while thefire is burning. The kitchen/dining/liv-ing room comprises a single volume ofair. If the extractor fan runs at the sametime as the fire, it will depressurise theroom and begin sucking smoke from thefire. In some installations you can getan auto bypass, so when you switch onan extractor hood, you might have an-other fan in place that will boost the ex-traction from a fireplace. Otherwise, youcould just open a window.

Young considered routing the warm airfrom the fire directly into the ducting ofthe heat recovery ventilation system, butdecided against it because of the hightemperature of the air. In any case, the warmair from the fire is being discharged into


7/8

CI 43

the open plan living/kitchen area and is

then distributed through the house by theHRV system, a Maico WS 250 provided byIrish Fan Distributors in Waterford. Acompact ventilation system, certified by thePassivhaus Institut in Darmstadt, thesystem also incorporates a geothermalbrine loop. Its actually using the heatof the ground to temper the fresh aircoming in, says Billy Wright of Irish FanDistributors. You have a constant tem-perature in the ground of between 7 and10 degrees. The loop allows you to usethat temperature to pre-heat the air inwinter and pre-cool it in summer. The50m loop runs along the northern andwestern sides of the house. Because ofthe prevalence of rock onsite, a longmound had to be created to achieve the1.5m depth required to take advantageof the constant soil temperatures. TheHRV system also incorporates a post-airheater, which is run via a heat exchanger

linked into the hot water system and

controlled by a single room thermostatin the utility room.

The solar panels are Solarfocus CPC col-lectors supplied by Renewable Energy Systemsand fitted by Penarch in Monaghan. Thesehybrid panels are guaranteed againstcondensation and the effects of corrosiveair. If you take flat plates, says PaulCarberry of Renewable Energy Systems,theyre vented top and bottom and mosthave 30mm of insulation at the back.CPC doesnt, which is a big advantage inIrish weather conditions. We suffer hugelyfrom condensation, which they donthave in mainland Europe where most ofthese products come from. Through thechanging of the seasons, particularly thefluctuations in temperature, the collectornever condensates internallyCondensa-tion causes problems by rotting the insu-lation at the back. So with conventional

flat plate, the efficiency ratings you hadquoted at the start, may, in three or fouryears mean nothing. The parabolic trayincorporated in CPC panels also facilitatesthe collection of sunlight up to fifty de-grees west and east of south, thereby al-lowing greater flexibility in panel placement.Because of the low pitched roof, the threepanels fully 7.2m2 had to be mountedon an A-frame on the roof to achieve theoptimal 45 degree angle. The panels feed

directly to the hot water tank, with anyexcess going to a buffer tank for use viathe heat exchanger in the HRV system.

Since moving into the house, the Youngfamily have found that between the post-heater in the HRV and basic hot water re-quirements, they rely on the back upimmersion far more than had been antic-ipated. To mitigate this power require-ment, and the impact it has on the BER,Young is now looking at adding an air-to-water heat pump.

In the meantime, the Proven 2.8kW windturbine is providing a substantial chunkof the houses electricity requirements.Also supplied by Renewable Energy Sys-

tems and fitted by Penarch, Paul Carberrysays the 2.8kW machine is perfectly sized:Youre not exporting a huge amount ofpower, and what you do export to the grid,youll get the full benefit of. The combi-nation of feed-in tariff arrangements re-cently announced by ESB and Eamon Ryanwill allow the exportation of 3,000 kilo-watt hours onto the grid per year for acombined tariff of 19c per KWh. Anyelectricity over that limit will earn the lowerrate of 10c.

We went with the Proven turbine, saysStephen Young, because theyve beenused for a long time in rugged terrainand on sites in the ocean, so they last.

Many of the cheaper turbines we lookedat would cut out in high windspeeds andstop generating, whereas the Proven tur-bine, the blades come in on themselvesduring high winds, so they still rotateand wont cut out. When you have wind,you want to keep using it. The systemrequires maintenance annually, which

(p41, top and bottom) the innovative I-joist timber frame system went up in just two anda half days with Solitex membranes to protect against moisture ingress

(above) live data on the performance of the Proven wind turbine; (right) the 2.8 kW windturbine provides a sizeable part of the houses electricity requirements


8/8

CI 45

can be completed in half a day, withoutthe use of any heavy machinery.

Tommy Kelly of Penarch, who installed

the turbine, says that Youngs site wasgood without being exceptional. A clear,unobstructed view of the southwest from which we get 90 per cent of ourwind is the prime consideration. Yourfirst job is site location. You have to analysethe site and find the best position for theturbine within the constraints of plan-ning and boundaries, then you mark whereyour foundations are going, you dig themout and pour them. Thats basically phaseone. Two separate sets of foundationsare required. The tower foundation, inwhich the baseplate for the tower ismounted, measures 3m by 3m by 1.2mdeep, while the foundation for the winchpin, which facilitates raising and loweringof the turbine itself, measures a metresquared. Phase two, you leave it two tothree weeks to cure the concrete, thenyou can mount your tower and put yourturbine on thatOnce you get your foun-

dations right, everything else falls intoplace. Since it was installed, the turbinehas drawn huge interest from passers-by.Young says at least two people everyweekend ring the bell to ask about it.

To further reduce electricity consumption,dimmable CFLs are used throughout, whileLEDs are fitted in the hall. Each unit pro-vides the equivalent of 50W of illumina-tion, while consuming only 2W of power.

Its not a huge abundance of light, saysYoung, but its sufficient for a corridor.

The house also boasts a Bord Na MonaRainSava rainwater harvesting system.Using the roof as a collector, the water isconducted to the 4,000L undergroundtank via the gutters and downpipes. In-side the tank, Bord Na Monas FrankMcKenna explains, theres a submersiblepump. Thats directed to a control panelthat can be placed in a utility room orthe garage. That will service your wash-ing machine, outside taps and toilets. Be-tween 60 and 70 per cent of the wateryou use in the house will be fed by theRainSava tank. The water is filtered intwo stages. Initially, a vortex filter is fit-

ted between the downpipes and the tankitself, while a second filter on the submersiblepump provides an additional level ofcomfort. Because the house is located ina hard-water area, using rainwater in thewashing machine prevents the lime-scaledamage that would otherwise occur.

Using the passive house methodology,Young estimates that the houses annualspace heating requirement at 13kWh/m2/a.From a BER rating point of view, its A2with the turbine, but if we refine ourcylinders and put in an extra heatsource, preferably a heat pump, it will goup to A1.

Passive house living does take a littlegetting used to, he says. The first nightwe moved in, in November, the housewas freezingSharon, my wife, thoughtthe house just wasnt working, it was socold. It took the guts of a month and ahalf to warm up. With a passive house, Iknew going into it that it would be dif-ferent in its first year cycle, and onceyou get a summer over, that youd buildup a lot of heat into the slab. A year onafter that, youd expect it to be that littlebit warmer coming into winter again.Right now, we have a comfortable 20 de-grees throughout the living areas and alittle less in the bedrooms.

SELECTED PROJECT DETAILS

Client: Stephen & Sharon Young

Designer/contractor: Young Design Build

Timber frame: A-frame Energy Efficient Homes

Air-tightness: Siga and Ecological Building Systems

Cellulose insulation: Collon Eco Insulation

Windows and doors: Ecoglaze

Fermacell boards: Richmond Building ProductsHeat recovery ventilation: Irish Fan Distributors

Solar thermal & wind turbine: Renewable EnergySystems

(above) Stephen Young, of Young Design Build, talking to Construct IrelandjournalistJohn Hearne; (below) the roof is also of I-joist construction with a cellulose insulation fill;(bottom) the utility room which houses the solar cylinder, buffer tank and heat recoveryventilation system

Documents

Construct Ireland Stephen Young