Useful tips to make your loft conversion an all-round success

Espe­cially under the roof, there is an enorm­ous poten­tial of extra liv­ing space wait­ing to be unlocked by a loft con­ver­sion. Our expert explains what needs to be con­sidered in plan­ning a con­ver­sion pro­ject and what to look out for when choos­ing products.

Tip 1: Check the building fabric and apply for funding

First, you should thor­oughly check the exist­ing build­ing fab­ric. How stable is the top floor ceil­ing? What con­di­tion is the roof truss in? Is the roof cov­er­ing water­tight and will it last a few more years? Inter­ested homeown­ers are best advised to cla­ri­fy these and oth­er ques­tions with the respect­ive experts. An (interi­or) archi­tect, a civil engin­eer or a build­ing sur­vey­or can provide valu­able assist­ance. Hir­ing a spe­cial­ist also makes sense because a loft con­ver­sion usu­ally requires the coordin­ated work of sev­er­al trades.

Good to know: If you use the ser­vices of an energy con­sult­ant, the Ger­man Fed­er­al Office for Eco­nom­ic Affairs and Export Con­trol (BAFA) will sub­sid­ize this by up to 80 per­cent. The BAFA also provides fund­ing for indi­vidu­al meas­ures on build­ings that improve their energy effi­ciency. For the energy optim­iz­a­tion of the build­ing envel­ope, includ­ing roof insu­la­tion and the install­a­tion of new win­dows, 15 per­cent of the eli­gible costs are cur­rently reim­bursed.

Tip 2: Decide on the future use of the new living space

After check­ing the build­ing fab­ric, the next step is plan­ning. How will the future liv­ing space under the roof be used? As a home office or as a sep­ar­ate liv­ing unit com­plete with bath­room and kit­chen? In this case, you need to pre­pare and install the sup­ply lines for elec­tri­city, water, sewage and pos­sibly also tele­phone and inter­net. Fur­ther­more, you need to cla­ri­fy wheth­er the exist­ing space and the incid­ent light under the roof are suf­fi­cient or wheth­er win­dows (don’t for­get a shad­ing device!), dormers or a raised knee wall are required. Atten­tion: All meas­ures that change the extern­al appear­ance of the build­ing are usu­ally sub­ject to approv­al.

Tip 3: Make sure there is good insulation and sufficient ventilation

The first step in an attic con­ver­sion is the prop­er pre­par­a­tion of the top floor ceil­ing. This is done, for example, by installing a dry screed with lev­el­ling fill. At the end of the con­ver­sion, the actu­al floor cov­er­ing can be laid. The install­a­tion of thermal insu­la­tion is indis­pens­able when con­vert­ing the attic. This not only keeps the heat in dur­ing the winter, but also the heat out in the sum­mer. Roof insu­la­tion, how­ever, is best left to a pro­fes­sion­al roof­er. Along with the insu­la­tion mater­i­al, you also need to install a vapor bar­ri­er to pre­vent thermal bridges where humid­ity con­denses and ulti­mately causes mold growth. Fur­ther­more, con­nec­tions to roof win­dows (e.g. sky­lights) and pen­et­ra­tions (e.g. for a satel­lite dish) must be tightly sealed. In addi­tion to thermal insu­la­tion, you need to ensure that the attic can be adequately vent­il­ated (e.g. by cross-vent­il­a­­tion) to provide a good indoor cli­mate. If roof win­dows are already in place, check wheth­er a replace­ment makes sense so that the insu­la­tion effect is not wasted. If neces­sary, also have the win­dow reveals insu­lated.