ᐅ Single-family house without a basement – creating additional usable space elsewhere

Created on: 26 Mar 2018 14:43

Hello everyone,

We are building our single-family house without a basement with the following specifications:

Gable roof with a 45° pitch
Knee wall 1m (3.3 ft)
Living area: 148 m² (1,593 sq ft)
House dimensions: 8.95m x 11.32m (29.4 ft x 37.2 ft)

We want to compensate for the lack of storage space from the missing basement through the following measures:

Make the attic accessible
Build an extended single garage
Build a spacious garden shed

I have questions regarding the following points:

1 - Attic:

This is a cold roof, meaning the floor between the upper floor and attic is insulated with mineral wool and has a vapor barrier in between.

The goal is to create more storage space. The attic is not intended to be used as living space.

For this purpose, I want to use tongue-and-groove boards, as these are vapor permeable compared to OSB panels and therefore prevent issues with rising moisture from the upper floor.

Questions:

So far, a pull-down attic ladder is planned. My wife prefers a fixed space-saving staircase with a railing for easier access. In my view, this should be no problem as long as the access hatch to the attic remains insulated. Are there suitable solutions for this?
We would also like to dry wet laundry in the attic. In our case, is this unproblematic? I believe the evaporated moisture could easily escape.
What do you think, how much effectively usable floor area would this create?
Do you have any personal experience with this?

The attached picture is provided as an example.

2 - Garage

The garage is planned to be 3.45m (11.3 ft) wide and 9m (29.5 ft) long. Inside the garage, a partition wall will be installed to separate the parking space from a storage area. Do you have recommendations for manufacturers or personal experience with this?

Thank you for your help.

Best regards,
Enno

hemali200328 Mar 2018 17:24

#31

11ant schrieb:
Nowadays, people also insulate between the ground floor and the upper floor.

However, both the ground floor and the upper floor are heated and ventilated.

11ant schrieb:
And even an uninsulated roof doesn’t create a zero difference between inside and outside. That means ventilation is still necessary.

Is that really the case? The uninsulated roof actually has some air movement (I believe the vapor barrier sheets overlap in many places but aren’t fully sealed everywhere). We actually couldn’t ventilate our attic except through the hatch...

Knallkörper28 Mar 2018 17:33

#32

hemali2003 schrieb:
Many people probably do this wrong.

Correct. The cold attic space stays dry only if there is air exchange. This means you need ventilation openings, no matter where or how. An open ridge alone is not enough. Roof windows with open ventilation slots alone are not sufficient either. You also need ventilation tiles and/or ventilation grilles in the gable walls. This is, of course, an effective but uncontrolled ventilation, which also helps reduce heat in summer. I have a climate logger in the attic and therefore know that the humidity has remained low throughout the past year.

However, insulating an uncontrolled ventilated attic does not make sense. In winter, cold air comes in through the ventilation, rendering the insulation ineffective. In summer, warm air enters, potentially causing condensation on the insulation. The advantage that the roof tiles’ thermal radiation heats the attic more slowly does not outweigh this disadvantage.

11ant28 Mar 2018 18:08

#33

hemali2003 schrieb:
We would not be able to ventilate our attic except through the hatch...

That is sufficient, it does not have to be a roof window. However, I would prefer gable vents. Or were you referring to the one in the retractable staircase?

https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

hemali200328 Mar 2018 18:10

#34

Yes, exactly! Only the retractable attic ladder. But I really don't know anyone who ventilates their attic...

hemali200328 Mar 2018 18:13

#35

I would find that strange too... I’m building a house with controlled mechanical ventilation, so the living areas wouldn’t need to be ventilated manually. But I still have to crawl into the attic to ventilate it once or twice a day?

Caspar202028 Mar 2018 18:15

#36

EnnoBecker schrieb:
Does anyone of you have insulated flooring in the attic plus insulation between the rafters?

hemali2003 schrieb:
The construction company told us that you either build a proper warm roof (sealed, insulated, with controlled ventilation) or a proper cold roof (unheated, slightly drafty, insulated only up to the heated area). There is basically no middle ground.

Since 1997, we have had a proper warm roof (18cm (7 inches) of insulation between the rafters; vapor barrier on the room side and drywall installed) and the ceiling between floors is also insulated (with a vapor barrier towards the living spaces). The beams are covered with tongue-and-groove boards.

We have a round window in the gable (which is rarely opened) and a standard access hatch with a pull-down ladder (so no insulated or special construction).

All of this was planned by the architect and carried out by the builder.

No moisture problems, mold, or anything similar have been detected so far.

(It should be noted that the drywall helps regulate humidity.)

ᐅ Single-family house without a basement – creating additional usable space elsewhere

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