Sealing windows properly

Drafts affect the com­fort and well-being and gen­er­ate expens­ive heat losses. In most cases, they are caused by leaks in the facade. One of the most crit­ic­al areas is the space between win­dow frame and masonry wall. If this area is not tightly sealed, res­id­ents will suf­fer from wintry con­di­tions in their own four walls. They lit­er­ally heat the out­doors instead of the liv­ing room. Here, the invest­ment in seal­ing tapes and seal­ants pays off. And when choos­ing res­id­ent- and envir­on­ment­ally friendly products, you will not only pre­vent drafts and heat loss but also pol­lut­ants. Make sure to keep the fol­low­ing tips in mind.

1. Blower Door Test

The Blower Door Test is par­tic­u­larly well suited for detect­ing pos­sible leaks. The test uses spe­cial equip­ment to cre­ate either a pos­it­ive or neg­at­ive pres­sure dif­fer­en­tial between inside and out­side. This pres­sure dif­fer­ence forces air through holes and pen­et­ra­tions in the build­ing shell and makes the leaks vis­ible.

2. How to plug leaks

In order to keep cold drafts and noise out­side, expert seal­ing is required to ensure a high degree of air and sound tight­ness. In accord­ance with the Ger­man Energy Sav­ing Ordin­ance (EnEV), the fol­low­ing prin­ciple applies: “Inside tight­er than out­side”. Oth­er­wise, the warm and humid room air will con­dense on the colder sur­faces and res­ult in mois­ture and mold dam­age. Thermal and sound insu­la­tion takes place in the middle insu­la­tion lay­er. The out­er lay­er should be open to dif­fu­sion so that mois­ture can escape to the out­side. It also pro­tects against wind and rain. Depend­ing on the mater­i­als used for win­dow frames and walls, leaks can be plugged with gun-applied seal­ants such as sil­ic­one. Oth­er gap fillers are cov­er strips, seal­ing tapes, foils/films and pro­files in vari­ous shapes and sizes, for example made of rub­ber-like TPE (ther­mo­plastic elast­omer).

3. How to ventilate properly

No mat­ter wheth­er you dry clothes, take a shower, cook a meal or just breathe – all these activ­it­ies pro­duce mois­ture. Only prop­er vent­il­a­tion of a well-insu­lated house can pre­vent the mold, which not only attacks the build­ing fab­ric but also your health. The key to a per­fectly insu­lated, draft-free home is there­fore purge (or cross) vent­il­a­tion: open the win­dows reg­u­larly and air the house briefly but intensely. Altern­at­ively, a vent­il­a­tion sys­tem can provide a reg­u­lar flow of fresh air.